JP2884922B2 - Positively charged toner and developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively chargeable toner used in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art In a developing process, a developer used in an electronic copying machine or the like is once attached to an image carrier such as a photoconductor on which an electrostatic image is formed, and then is transferred to a photoconductor in a transfer process. Is transferred to the transfer paper, and is fixed on the copy paper surface in a fixing step. At this time, as a developer for developing an electrostatic charge image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner and a one-component developer (a magnetic toner, a non- Magnetic toners) are known.

As the toner contained in the developer, there are a positively charged toner and a negatively charged toner. Conventionally, as a toner which imparts chargeability to the positively charged toner, a nigrosine dye, a quaternary ammonium salt is used. For example, a charge controlling agent as an additive to a toner, a coating agent for imparting a predetermined chargeability to a carrier, and the like have been known. Already high-quality, high-quality photocopiers equipped with organic photoconductor photoconductors
Due to demands for high performance such as high durability, high speed, and shortening of copying work time, it has been already adopted to use a developer in which a ferrite carrier and a toner containing a quaternary ammonium salt compound are combined. For example, Company A copier 1
(Copy speed: 40 sheets / A4 / min) The developer for styrene / acrylic resin, carbon black,
It comprises a toner containing a quaternary ammonium salt compound (of the following general formula [I]) and the like, and a carrier obtained by coating a Cu-Zn-ferrite core material with a fluorine resin.
FIG. 1 shows the result of differential thermal analysis (DTA) of the toner of Company A.
Of the toner P. In addition, Company B copier 2 (copy speed:
25 sheets / A4 / min) and the developer for copier 3 (copy speed: 50 sheets / A4 / min)
It is composed of a toner containing an acrylic resin, carbon black, a quaternary ammonium salt compound (the following formula [I]) and the like, and a carrier coated with a Cu-Zn-ferrite core material with a silicone resin. The results of differential thermal analysis (DTA) of the toner of Company B are shown in FIG.
Are shown in toners Q and R. The toners P, Q,
In R, only one absorption peak of the quaternary ammonium salt compound was confirmed.

Incidentally, the identification of the quaternary ammonium salt compound in the toner can be carried out by analyzing by thermal decomposition chromatography, X-ray diffraction, nuclear magnetic resonance spectroscopy and the like.

[0005]

However, in these conventional toners, the effect of imparting chargeability by the quaternary ammonium salt compound is not sufficiently obtained, and there is a problem to be further improved. For example, the charge build-up property of the toner (the time from when the copying machine or the like is started and mixing with the carrier is started until a predetermined charge amount is obtained), the stability of image density during continuous use, the occurrence of fog (image stain), There has been a problem in that the inside of the copying machine is stained due to toner scattering inside the copying machine. As another example, it is difficult to stably exhibit appropriate chargeability of the toner irrespective of the environment and the like, and it is difficult to obtain a preferable form with the change over time of the charge. If the toner or developer is exposed to high temperature for a long time during transportation or storage in a warehouse, image contamination such as fog occurs when continuous copying is performed using such toner or developer, or the inside of the machine due to toner scattering The problem of the occurrence of dirt was a problem.

[0006]

Means for Solving the Problems As a result of diligent studies of the above-mentioned problems, the present inventors have found that the quaternary ammonium salt compound in the toner is brought into a specific state so that the image quality is less changed with time and the deterioration due to the environment is small. In addition, they have found that a toner having excellent charging characteristics can be obtained, and have reached the present invention.

That is, the gist of the present invention is that, in a toner containing at least a resin, a colorant and a quaternary ammonium salt compound, the quaternary ammonium salt compound in the toner has two absorption peaks by thermal analysis. Attainable with a positively charged toner. Further, a toner containing at least a resin, a colorant, and a quaternary ammonium salt compound, wherein the quaternary ammonium salt compound in the toner is a positively charged toner having two peaks by thermal analysis, And a developer containing a silicone resin-coated carrier.

[0008]

Hereinafter, the present invention will be described in detail. As the resin component usable in the present invention, various known resin components suitable for toner can be used. For example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer,
Styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-
Acrylic ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer,
Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic ester copolymer (styrene-methyl methacrylate copolymer, styrene-methacrylic) Ethyl acrylate copolymer, styrene-butyl methacrylate copolymer and styrene-phenyl methacrylate copolymer), styrene-α-methyl methyl acrylate copolymer, styrene-acrylonitrile-acrylate copolymer and the like. Styrene-based resin (a homopolymer or copolymer containing styrene or a styrene substituent),
Vinyl chloride resin, rosin-modified maleic resin, phenol resin, epoxy resin, polyester resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral There are resins, polycarbonate resins, and the like. Particularly preferred resins for use in the present invention include styrene resins, saturated or unsaturated polyester resins, and epoxy resins. In addition, the above resins are not limited to being used alone, and two or more kinds can be used in combination.

Furthermore, a crosslinked binder resin described in JP-B-51-23354 and JP-A-50-44836, or JP-B-55-6895 and JP-B-63.
Non-crosslinked binder resins described in JP-A-32180 can also be used. The glass transition temperature of the binder resin for the toner is preferably 50 ° C. or more at the start of transition (inflection point) as measured by a differential thermal analyzer. When the glass transition temperature is lower than 50 ° C., when the toner is left at a high temperature of 40 ° C. or higher for a long time, the toner may be aggregated or fixed, which causes a problem in use.

The coloring agent used in the present invention is not particularly limited as long as it is conventionally used.
Any suitable pigment or dye can be used. For example, titanium oxide, zinc white, alumina white, calcium carbonate, navy blue, carbon black, phthalocyanine blue,
A colorant is used alone for the toner color corresponding to phthalocyanine green, Hansa Yellow G, rhodamine-based pigments, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane-based dyes, anthraquinone dyes, monoazo and disazo-based dyes and pigments Or mix and use.

The content of the colorant may be sufficient to color the toner so that a visible image can be formed by development. For example, the content is 1 to 20 parts by weight with respect to 100 parts by weight of the resin. Is preferred. As the quaternary ammonium salt compound used in the toner of the present invention, specifically, a compound represented by the following general formula [I] is preferably exemplified.

[0012]

Embedded image

A synthesis example for obtaining the quaternary ammonium salt compound [I] is shown below. An aqueous solution of benzyltributylammonium chloride is appropriately diluted with water, and while stirring, a solution of sodium 4-hydroxynaphthalenesulfonate appropriately dissolved in water is added dropwise to the diluted solution at room temperature. Then, the temperature was raised to about 85 ° C., and the reaction was carried out for about 1 hour. The mixture is cooled to near room temperature with stirring, filtered, washed with water and dried to obtain the compound [I].

Compounds (I) which are already commercially available include, for example, Bontron P manufactured by Orient Chemical Co.
There are 51. A feature of the present invention is that the quaternary ammonium salt compound in the toner has two endothermic peaks by thermal analysis, and if there is one endothermic peak or no endothermic peak, the charging characteristics of the toner are poor, which is not preferable. .

The present inventors have found that the endothermic peak in thermal analysis of the compound changes depending on the difference in toner production conditions. That is, the compound alone has two endothermic peaks, but the endothermic peak of the compound in the toner changes from the two peaks to one peak and further no peak due to a difference in toner manufacturing conditions. Then, in a state where the compound in the toner after production has two endothermic peaks, the charging performance and the like of the toner become good. Furthermore, even when the toner has two endothermic peaks in the toner, the first
When the peak area is equal to or larger than the high-temperature peak area, the charging performance and the like of the toner are further improved.

The ratio of low-temperature peak area / high-temperature peak area is 0.
It is good to be about 1 to 3.2, preferably 0.6 to 3.2, more preferably 1.0 to 3.2. In addition, the endothermic peak of the compound in the toner is greatly affected by the kneading step in the toner manufacturing process, and the control is performed by controlling the kneading conditions such as the kneading temperature, the extruding amount, and the screw configuration even with the same extruder or the same extruder. It may be performed by adjusting.

The thermal analysis may be performed by confirming the state of an endothermic peak from a curve measured at a temperature rising rate of 10 ° C./min using a commercially available differential thermal analyzer, differential scanning calorimeter, or the like. The content of the quaternary ammonium salt compound in the toner of the present invention is preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 8 parts by weight. If the content of this compound is too small, the effect of improving the chargeability of positive charge cannot be expected,
If the amount is excessive, the quality of the toner deteriorates, which is not preferable.

Further, as a charge control agent other than the present compound,
Other quaternary ammonium salt compounds, polyamine resins, nigrosine-based compounds, triaminotriphenylmethane-based compounds, imidazole-based compounds and the like may be used in combination, but the amount used is smaller than the amount of the compound of the present invention. , Preferably 以下 or less. In addition, if necessary, a small amount of an auxiliary agent may be added for the purpose of improving the thermal characteristics and physical characteristics of the toner. For example, polyalkylene wax, paraffin wax, higher fatty acid, fatty acid amide, metal soap and the like can be used. The addition amount is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the toner particles.

Further, the fluidity of the toner on the surface of the toner particles,
For the purpose of improving coagulation resistance, adjusting toner resistance, and controlling chargeability, it is also possible to add metal oxide fine powders such as titania, silica, alumina, magnetite, and ferrite and organic fine powders such as acrylic resin alone or as a mixture. It is possible. The addition amount is 0.01 to 100 parts by weight of the toner particles.
About 5 parts by weight is preferable.

As the method for producing the toner particles, various conventional toner production methods can be applied. For example, as a general example, first, a resin, a colorant, a wax, a charge control agent and the like are mixed in a known mixer. Then, the mixture may be melt-kneaded in a closed kneader or a single-screw or twin-screw extruder, cooled, pulverized, and classified. In recent years, single-screw or twin-screw extruders have become the mainstream because of their advantages such as continuous production. For example, KTK twin-screw extruders manufactured by Kobe Steel, TEM extruders manufactured by Toshiba Machine Co., Ltd. A twin screw extruder manufactured by CK Corporation, a PCM type twin screw extruder manufactured by Ikegai Iron Works, or a kneader manufactured by Buss is preferred.

It is also preferable to subject the present compound to a masterbatch treatment with a resin in advance. The average particle size of the toner is 3 to 2
0 μm is preferred. Further, when the toner is externally added, the classified toner and the external additive may be stirred and mixed with a high-speed stirrer or the like. The obtained toner of the present invention is a one-component developer not using a carrier, a magnetic one-component toner containing a magnetic substance such as magnetite, or a non-magnetic one toner containing no magnetic substance.
It can also be used as a component toner.

When the toner of the present invention is used for a two-component developer, it may be used by mixing with a magnetic carrier. Examples of the magnetic carrier include iron powder, ferrite powder, and magnetite powder having an average particle diameter of about 20 to 200 μm. A conventionally known material such as a magnetic resin carrier can be used. Further, those whose surfaces are coated with a known silicone resin, acrylic resin, fluorine resin, styrene resin, epoxy resin, polyester resin, polyamide resin, or the like, or a mixture of these resins can also be used.

As the core material of the carrier, ferrite powder containing magnetite is preferable. Further, the coat layer of the carrier may be a single layer or a multilayer, but it is preferable that the uppermost layer on the surface is adjusted so as to be coated with at least a methyl silicone-containing resin or a phenyl silicone-containing resin. The silicone resin is composed of macromolecules in which silicon atoms are bonded to each other via siloxane bonds and extend in a network, and are bonded only to other three or less silicon atoms on the surface of the macromolecules via siloxane bonds. The unreacted silicon atom usually has a hydroxyl group, and a resin in which at least a part of the hydroxyl group is replaced with a methyl group or a methyl group and a phenyl group is referred to as a methylsilicone-containing resin and a phenylsilicone-containing resin, respectively.

The carrier may be mainly composed of a ferrite carrier coated with a silicone resin, and may be used by blending a ferrite carrier coated with another resin.
The blend ratio at that time is preferably less than 50%, and more preferably 40% or less. Although there is no particular limitation on the particle size of these carriers, those having an average particle size of 10 to 200 μm are preferred. The mixing ratio of the carrier and the toner is preferably 5 to 100 parts by weight with respect to 1 part by weight of the toner.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In the following examples, “parts” simply means “parts by weight”.

<Example 1>

[Table 1] ・ Styrene / n-butyl acrylate = 82/18 copolymer resin a 100 parts (flow softening point 130 ° C., glass transition point 61 ° C.) ・ Colorant carbon black MA-7 5 parts (manufactured by Mitsubishi Chemical Corporation)・ 2 parts of low molecular weight polypropylene 550P (manufactured by Sanyo Chemical Industries, Ltd.) ・ 2 parts of quaternary ammonium salt compound Bontron P51 (general formula [I]) (manufactured by Orient Chemical Co., Ltd.), and use a continuous twin screw extruder 7kg /
The mixture was kneaded, pulverized and classified under the conditions of an outlet temperature of 159 ° C. for a time to obtain a black toner a having an average particle diameter of 10 μm.

FIG. 2 shows the result of thermal analysis of the toner a. Two endothermic peaks of the compound [I] were confirmed, and the charge rising characteristics are shown in FIG. 3. The charge rising is good and almost stable. . The ratio of low-temperature peak area / high-temperature peak area was about 3.0. 0.15 parts of silica powder (R972 manufactured by Nippon Aerosil Co., Ltd.) was externally added to 100 parts of the black toner a with a Henschel mixer to obtain a toner A. 4 parts of the obtained toner A and 100 parts of a Cu—Zn ferrite powder carrier having an average particle diameter of 100 μm and surface-coated with a methyl silicone-containing resin were mixed and stirred to prepare a developer A.

Next, each of the starting developer A and the replenishing toner A is put into a bottle, and the bottle is hermetically sealed.
After being stored for 10 days in an environment of 5 ° C. and 50% humidity and cooled, an organic photoconductor was used as a photoconductor, a fixing machine coated a thin layer of Teflon resin on silicone rubber, and a heater lamp was mounted inside the roller. It is composed of an upper heat roller and a lower pressure roller made of silicone rubber. The fixing temperature is set to 190 ° C. without supplying a releasing liquid such as silicone oil, and the temperature is adjusted to 23 ° C. using a copying machine with a copy speed of 50 sheets / min.
Under environmental conditions of ~ 25 ° C and humidity of 60 ~ 65% RH,
A real-life test of 000 sheets was performed. The results of the actual test are shown in Table 1. As shown in FIG. 1, there is no increase in fog, which is a stain on the white background of the copy, and the density of the black background is stably high even during the actual shooting of 20,000 sheets. The toner and the developer were excellent without contamination, and had excellent durability performance and copy image stability even when used after being exposed to a high temperature for a long time.

<Example 2>

[Table 2] ・ Styrene / n-butyl acrylate = 82/18 copolymer resin a 90 parts (flow softening point 130 ° C., glass transition point 61 ° C.) ・ Quaternary ammonium salt compound Bontron P51 10 parts (manufactured by Orient Chemical Co., Ltd.) And the same twin-screw extruder as in Example 1 was used to extrude 7
The mixture was kneaded and coarsely pulverized under the conditions of kg / hour and an outlet temperature of 165 ° C. to obtain a mixture b.

Further,

[Table 3]-20 parts of mixture b-82 parts of styrene / n-butyl acrylate = 82/18 copolymer resin-82 parts of colorant carbon black MA-7 5 parts (manufactured by Mitsubishi Kasei)-2 parts of low molecular weight polypropylene 550P ( And then kneading, pulverizing and classifying again using a twin screw extruder under the conditions of an extrusion rate of 7 kg / hour and an outlet temperature of 159 ° C. to obtain a black toner b having an average particle diameter of 10 μm. Was. FIG. 2 shows the result of the thermal analysis of the toner b. Two endothermic peaks of the compound [I] were confirmed, and the charge rising characteristics are shown in FIG. 3. The charge rising is good and the stability is good. The ratio of low-temperature peak area / high-temperature peak area was about 1.0.

Next, the toner B and the developer B were obtained by externally adding the toner b and mixing with the carrier in the same manner as in Example 1, and the heat treatment and the actual printing test were performed in the same manner as in Example 1. The results of the actual test are shown in Table 1. The results were almost the same as in Example 1.

Comparative Example 1 A toner c was obtained in the same manner as in Example 1 except that the kneading conditions in the kneading step were changed to an extrusion rate of 7 kg / hour and an outlet temperature of 170 ° C. FIG. 2 shows the result of the thermal analysis of the toner c. One endothermic peak of the compound [I] is confirmed to be small, and the charge rising characteristic is shown in FIG. 3. However, the charge rising is low and the stability is poor.

Next, the toner C and the developer C were obtained by externally adding the toner c and mixing with the carrier in the same manner as in Example 1, and a heat treatment-actual copying test was performed in the same manner as in Example 1. Table 1 shows the results of the live-action test.
During actual copying of 000 sheets, fog, which is a stain on a copy white background, has increased, especially immediately after the replenishment of the replenishing toner to the developer has started.

Comparative Example 2 A toner d was obtained in the same manner as in Example 1 except that the kneading conditions in the kneading step were changed to an extrusion rate of 7 kg / hour and an outlet temperature of 193 ° C. The result of thermal analysis of this toner d is shown in FIG. 2, and there is no endothermic peak of the compound [I], and the charge rising characteristic is shown in FIG. 3. However, the charge rising is very low and the stability is poor.

Next, the toner D and the developer D were obtained by adding the toner d to the toner D and the developer D in the same manner as in Example 1, and the heat treatment and the actual printing test were performed in the same manner as in Example 1. Table 1 shows the results of the live-action test.
During actual copying of 000 sheets, fog, which is a stain on a copy white background, increased immediately after the start of replenishment of replenishment toner to the developer, and there was a problem that contamination due to toner scattering in a copying machine was noticeably increased.

[0036]

[Table 4]

[Brief Description of Measurement Method] (1) Endothermic peak of compound [I] in the toner: using a differential thermal analyzer (model: DTA-40) manufactured by Shimadzu Corporation.
From room temperature to 250 ° C, heating rate in air atmosphere 10 ° C /
The temperature was measured in minutes. (2) Charging start-up characteristics: 4 parts of toner and 100 parts of ferrite carrier (F-100 manufactured by Powdertech) were mixed and stirred, and the toner charge was measured using a blow-off charge meter measuring device manufactured by Toshiba Chemical Corporation. . (3) Fog: Copy paper was measured with a color difference meter manufactured by Nippon Denshoku Co.
(Whiteness) was measured, and fog = Wb1−Wb2 was determined from whiteness before copying (Wb1) and whiteness after copying (Wb2).

[0038]

The positively chargeable toner and developer of the present invention are:
It has good charging performance, such as good charging start-up property, and always shows appropriate and stable charging properties.
After exposing toner and development to high temperature of ℃ or more for a long time, even when continuous copying is performed using these, there is no image stain such as fog, and a stable copy density can be obtained. This provides a great industrial benefit, such as little contamination due to toner scattering.

[Brief description of the drawings]

FIG. 1 is a thermal analysis curve of a commercially available toner.

FIG. 2 is a thermal analysis curve of toners a, b, c, and d.

FIG. 3 is a graph showing the charging rise characteristics of toners a, b, c, and d.

Claims (2)

(57) [Claims] 1. A toner comprising at least a resin, a colorant and a quaternary ammonium salt compound, wherein the quaternary ammonium salt compound in the toner has two absorption peaks by thermal analysis. . 2. A toner containing at least a resin, a colorant and a quaternary ammonium salt compound, wherein the quaternary ammonium salt compound in the toner has two absorption peaks by thermal analysis. A developer containing a silicone-based resin-coated carrier containing ferrite as a core material.