JPH0577069B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a new toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like. [Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 2297691
No., Special Publication No. 1972-23910, and Special Publication No. 43-
Various methods are described in Japanese Patent No. 24748, etc., but they basically involve applying a uniform electrostatic charge onto a photoconductive insulating layer and irradiating the insulating layer with a light image. An electrostatic latent image is formed, and then this latent image is developed and visualized using a fine powder called toner in this technology, and if necessary, the powder image is transferred to paper, etc., and then heated, pressurized, or solvent vapor is applied. Fixation is carried out by such methods. The developing methods applied to these electrophotographic methods can be roughly divided into dry developing methods and wet developing methods. The former method is further divided into a method using a two-component developer and a method using a single-component developer. Two-component developing methods include a magnetic brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, etc., depending on the type of carrier for conveying the toner. Furthermore, the one-component development methods include the powder cloud method, in which toner particles are sprayed, and the contact development method, in which toner particles are brought into direct contact with the electrostatic latent image surface. (also referred to as toner development), jumping development method in which toner particles are not brought into direct contact with the electrostatic latent image surface, but are charged and flown toward the latent image surface by the electric field of the electrostatic latent image; magnetic conduction There is the MagneDry method, which develops by bringing a toner into contact with the electrostatic latent image surface. As toners applied to these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. For example, particles obtained by dispersing a colorant in a binder resin such as polystyrene and pulverizing the particles to about 1 to 30 μm are used as toner. As the magnetic toner, one containing magnetic particles such as magnetite is used. In the case of a method using a so-called two-component developer, the toner is usually mixed with carrier particles such as glass beads or iron powder.
Further, the toner is made to have a positive or negative charge depending on the polarity of the electrostatic latent image to be developed. In order to make the toner hold an electric charge, it is also possible to utilize the triboelectricity of the resin that is a component of the toner, but in this method, the toner's chargeability is small, so the image obtained by development is prone to fogging.
It becomes unclear. Therefore, in order to impart desired triboelectric chargeability to the toner, dyes and pigments that impart chargeability, as well as charge control agents, are added. Charge control agents known in the art today include the following: (1) The following substances are used to control toner to be positively charged. Nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 1627/1983), basic dyes (for example, CIBasic Yellow 2 (C.
I.41000), CIBasic Yellow 3, CIBasic
Red 1 (CI45160), CIBasic Red 9 (C.
I.42500), CIBasic Violet 1 (CI42535), C.
I.Basic Violet 3 (CI42555), CIBasic
Violet 10 (CI45170), CIBasic Violet 14 (C.
I.42510), CIBasic Blue 1 (CI42025), CI
Basic Blue 3 (CI51005), CIBasic Blue
5 (CI42140), CIBasic Blue 7 (CI42595)
,
CIBasic Blue 9 (CI52015), CIBasic
Blue 24 (CI52030), CIBasic Blue 25 (C.
I.52025), CIBasic Blue 26 (CI44045), CI
Basic Green 1 (CI42040), CIBasic Green
4 (CI42000), CI42510, CI45170, etc., lake pigments of these basic dyes, (lake-forming agents include phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferridianide) , ferrocyanide, etc.), CISolvent
Black 3 (CI26150), Hansa Yellow G (C.
I.11680), CIMordlant Black 11, CI
Pigment Black 1, Gilsonite, Asphalt, etc. Quaternary ammonium salts, such as benzolmethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, organic complex compounds such as dibutyltin oxide, metal salts of higher fatty acids, inorganic fine powders such as glass, mica, and zinc oxide, EDTA, acetylacetone Polyamine resins such as metal complexes, vinyl polymers containing amino groups, condensation polymers containing amino groups, etc. (2) The following substances are used to control the negative chargeability of toner. Special Publication No. 41-20153, No. 43-27586
Metal complex salts of monoazo dyes described in No. 44-6397, No. 45-28478, etc. Tokukai 1975
- Dye and pigments such as nitrofumic acid and its salts or CI14645 described in No. 133338, Special Publication No. 1984-42752, Special Publication No. 58-41508, Special Publication No. 59
Metal complexes such as Co, Cr, and Fe of salicylic acid, naphthoic acid, and dicarboxylic acids, sulfonated copper phthalocyanine pigments, nitro groups, and halogen-introduced styrene described in Japanese Patent Publication No. 7384 and Japanese Patent Publication No. 58-7385, etc. Oligomers, chlorinated paraffin, melamine resin, etc. Many of these charge control agents are derived from facial cleansers, and generally have complex structures and many of them have strong coloring properties. There are some new products that have been proposed recently that are different from these, but none have surpassed facial cleansers in terms of overall performance, and there are still examples that use dyes, although they are still unsatisfactory. Almost. These are usually added to thermoplastic resins, thermally melted and dispersed, and then finely pulverized and adjusted to a suitable particle size as necessary before use. However, these dyes used as charge control agents have complex structures, inconsistent properties, and poor stability. In addition, it is likely to be decomposed or altered due to decomposition during thermal kneading, mechanical impact, friction, changes in temperature and humidity conditions, etc., and a phenomenon in which charge controllability is likely to occur is likely to occur. Therefore, when a toner containing these dyes as a charge control agent is used for development in a copying machine, the charge control agent may decompose or change in quality as the number of copies increases, which may cause deterioration of the toner during durability. . Furthermore, since it is extremely difficult to uniformly disperse these charge control agents in thermoplastic resins, they have the fatal drawback of causing a difference in the amount of frictional charge between toner particles obtained by pulverization. are doing. For this reason, various methods have been used to achieve more uniform dispersion. For example, basic nigrosine dyes are used by forming salts with higher fatty acids in order to improve their compatibility with thermoplastic resins, but unreacted fatty acids or salt dispersion products often remain on the toner surface. When exposed, it contaminates the carrier or toner carrier, causing a decrease in toner fluidity, fogging, and a decrease in image density. Alternatively, in order to improve the dispersion of these charge control agents into the resin, a method has also been adopted in which charge control agent powder and resin powder are mechanically pulverized and mixed in advance and then hot melt-kneaded. However, the inherent poor dispersion cannot be avoided, and at present, sufficient uniformity of charge has not yet been obtained for practical use. Further, most of the substances generally known as charge control agents have a dark color and cannot be incorporated into a bright chromatic developer. In addition, many charge control agents are hydrophilic, and due to poor dispersion in these resins, after melt-kneading,
When crushed, the dye is exposed on the toner surface. Therefore, when the toner is used under high humidity conditions, it has the disadvantage that a good quality image cannot be obtained because these charge control agents are hydrophilic. In this way, when conventional charge control agents are used in toner, charge control agents occur between toner particles, between toner and carrier, or between toner and toner carriers such as sleeves, and on the surface of toner particles. This causes variations in the amount of charge generated, and problems such as development fog, toner scattering, and carrier contamination are likely to occur. Further, this problem becomes a noticeable phenomenon when a large number of copies are made, and the result is practically unsuitable for copying machines. Furthermore, under high humidity conditions, the transfer efficiency of toner images decreases significantly, and many of them become unusable. Even at room temperature and humidity, when the toner is stored for a long period of time, it often undergoes deterioration due to the instability of the charge control agent used and becomes unusable due to poor charging properties. Furthermore, when conventional charge control agents are used in toners, long-term use can cause the charge control agents to adhere to the surface of the photoreceptor or promote toner adhesion, adversely affecting latent image formation or causing (filming phenomenon) ), there are many substances that have a negative effect on the cleaning process of a copying machine, such as those that cause scratches on the surface of the photoreceptor or cleaning members such as cleaning blades, or accelerate wear of the members. Furthermore, when conventional charge control agents are used in toners, many of them have a large effect on the thermal melting properties of the toners and reduce fixing performance. In particular, it deteriorates the high temperature offset performance and increases the tendency of the transfer paper to cling to the roller during heat roll fixing. There are some things that reduce the durability life of the roller. As described above, conventional charge control agents have many drawbacks, and there is a strong demand in the technical field to improve these, and although many improvement techniques have been proposed, there is still no practical comprehensive approach. The reality is that nothing satisfying has been found. [Problems to be Solved by the Invention] An object of the present invention is to provide a new technique for controlling the charge of toner that overcomes the above-mentioned drawbacks. The object of the present invention is to stabilize the amount of triboelectric charge between toner particles, between toner and carrier, or between toner and a toner carrier such as a sleeve in the case of one-component development, and to sharpen the abrasion charge amount distribution. The purpose of the present invention is to provide a developer which is uniform and whose charge amount can be controlled to suit the developing system used. Still another object is to use a developer for faithfully developing and transferring the latent image, i.e., without toner adhesion in the background area during development, without fogging, and without toner scattering around the edges of the latent image.
To provide a developer capable of obtaining high image density and good halftone reproducibility. Still another object is to provide a developer that maintains its initial characteristics even when the developer is used continuously over a long period of time, and that causes no toner aggregation or change in charging characteristics. Another objective is to develop a developer that reproduces stable images that are unaffected by changes in temperature and humidity, especially a developer that has high transfer efficiency and does not cause scattering or transfer dropouts during transfer at high or low humidity. It's on offer. Still another object is to provide a bright chromatic developer. Still another object is to provide a developer with excellent storage stability that maintains its initial characteristics even during long-term storage. Still another object is to provide a developer that does not stain, abrade, or scratch the electrostatic latent image surface and is easy to clean. Still another object is to provide a developer having good fixing properties, especially a developer free from problems such as high temperature offset. [Means and effects for solving the problems] The present invention is directed to a toner for developing electrostatic images characterized by containing a triazine condensate. The present inventors have discovered that a triazine compound has sufficient abrasion charging properties and, when contained in a developer, is a charge control agent that provides a developer with good electrophotographic properties. However, some triazines that have sufficient abrasion charging properties have some problems with their stability, and triazines that can achieve both compound stability and abrasion charging ability have a certain limited structure. It will be limited to. In addition, even if triazine has both stability and abrasion charging ability,
Due to too much consideration given to the balance between the two, the abrasion charging ability is limited to some extent. The present inventors investigated triazine that has sufficient abrasion charging ability and is thermally and chemically stable. As a result, the inventors found that a so-called triazine condensate, which is a condensation of at least two or more triazine rings, was found to be more effective than a monomer. Rather, it was found that the abrasion charging ability is high and the thermal and chemical stability is increased. As a result, even triazine, which has insufficient abrasion charging ability as a monomer, can be condensed to improve its abrasion charging ability to the extent that it can be used as a charge control agent. On the other hand, by condensing triazine, which has a problem with stability, the stability increases and the stability can be improved to the point where there is no problem in practical use. That is, we have succeeded in developing triazine that has both stability and triboelectric charging ability, and it is now possible to make triazine, which has conventionally been unusable as a monomer, fully usable. Triazine monomers are essentially colorless, but as the degree of condensation increases, they begin to become slightly colored. When used in color toners, the degree of condensation is preferably 10 or less. Furthermore, when a triazine condensate is used as a charge control agent, a developer can be obtained that can provide images with better resolution than when other charge control agents are used. The present invention is characterized by an electrostatic image developing toner containing a condensate of a compound having a triazine skeleton, and the condensate basically has at least two triazine rings. On the other hand, if a triazine ring is present, the performance as a charge control agent is not greatly affected by the substituents on the triazine ring.
Therefore, the triazine monomer is not particularly limited, but it is preferable that a halogen element such as chlorine is not directly bonded to the triazine ring. An example of a triazine condensate useful in the present invention is shown below, but as mentioned above, any condensate of triazine can be used in the present invention, and the present invention is not limited to the following compounds. do not have.

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〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but these are not intended to limit the present invention in any way. All parts in the following formulations are parts by weight. Example 1 Styrene/butyl methacrylate (80/20) copolymer 100 parts Carbon black 5 parts Low molecular weight polyethylene wax 2 parts Compound (2) After thoroughly mixing the above materials in a blender, 150 parts
The mixture was kneaded using two rolls heated to ℃. After the kneaded material was left to cool naturally, it was roughly pulverized using a cutter mill, then pulverized using a pulverizer using jet air flow, and further classified using an air classifier to obtain a fine powder with a particle size of 5 to 20μ. . A developer was prepared by mixing 5 parts of the fine powder with 100 parts of iron powder carrier having an average particle size of 50 to 80 microns. Next, a negative electrostatic image is formed on the OPC photoreceptor by a conventionally known electrophotographic method, and this is powder-developed using the above-mentioned developer using a magnetic brush method to create a toner image, which is then transferred to plain paper. It was fixed by heating. The resulting transferred image had a sufficiently high density, no fogging, and no toner scattering around the image, resulting in a good image with high resolution. Further, during durability, the above-mentioned filming phenomenon related to toner on the photoreceptor was not observed at all, and no problems were found in the cleaning process. Also, there were no troubles in the fixing process at this time, and after the durability test of 30,000 sheets, the fuser was observed, and there were no scratches or damage to the rollers, and there was almost no dirt from offset toner, so there was no problem at all in practical use. Ta. In addition, when the environmental conditions were set to 35℃ and 85%, the image density was almost unchanged from normal temperature and humidity.
A clear image was obtained without fogging or scattering. Next, when a transferred image was obtained at 15° C. and 10% low temperature and low humidity, the image density was sufficiently high, solid black was developed and transferred extremely smoothly, and the image was excellent with no scattering or hollow spots. Comparative Example 1 A developer was obtained in the same manner as in Example 1, except that 2 parts of nigrosine dye (Nigrosine Base EX manufactured by Orient Chemical Industry Co., Ltd.) was used instead of 2 parts of compound ().
Development, transfer, and fixing were performed to obtain an image in the same manner. At room temperature and humidity, there is little fog, but the image density is 1.06.
The line drawings were scattered, and the solid black was noticeably rough. Also, during durability, after about 10,000 copies, the toner material formed a thin, streak-like film on the surface of the photoreceptor and began to appear as lines on the image. This is so-called filming, and is thought to be due to the charge control agent changing the lubricity of the toner powder. Also, during durability testing, the fixed image tended to get caught up in the fixing roller during the fixing process, and there was difficulty in peeling it off from the roller. When images were obtained at 35°C and 85%, the image density was as low as 0.88, and fogging, scattering, and roughness increased. Transfer efficiency was also low. When an image was obtained under conditions of 15°C and 10%, the image density was as low as 0.91, and there was severe scattering, fogging, roughness, and transfer omissions. Example 2 A developer was obtained in the same manner as in Example 1 except that 3 parts of compound (2) was used instead of 2 parts of compound (1), and an image was obtained in the same manner by performing development, transfer, and fixing. Detailed results are shown in Tables 1 and 2, but Example 1
Almost the same satisfactory results were obtained. Example 3 A developer was obtained in the same manner as in Example 1 except that 5 parts of compound (3) was used instead of 2 parts of compound (1), and development and
Transfer and fixing were performed to obtain an image in the same manner. The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained. Example 4 A developer was obtained in the same manner as in Example 1 except that 7 parts of compound (4) was used instead of 2 parts of compound (1), and development and
Transfer and fixing were performed to obtain an image in the same manner. The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 1 were obtained. Example 5 Styrene/butyl methacrylate (80/20) copolymer 100 parts (weight average molecular weight Mw: approximately 350,000) Triiron tetroxide EPT-500 (manufactured by Toda Kogyo) 60 parts Low molecular weight polypropylene wax 2 parts Compound ( 1) 2 parts After mixing the above ingredients well in a blender, 150
The mixture was kneaded using two rolls heated to ℃. After the kneaded material was left to cool naturally, it was roughly pulverized using a cutter mill, then pulverized using a pulverizer using jet air flow, and further classified using an air classifier to obtain a fine powder with a particle size of 5 to 20μ. . Next, 0.4 parts of amino-modified silicone oil-treated hydrophobic colloidal silica (manufactured by Nippon Aerosil Co., Ltd.) was mixed with 100 parts of the fine powder using a sample mill to prepare a one-component magnetic toner. Apply this toner to a commercially available copier (product name NP-
150Z (manufactured by Canon Inc.) to produce an image, almost the same results as in Example 1 were obtained. Example 6 In Example 5, instead of 2 parts of compound (1),
A developer was obtained in the same manner as in Example 5, except that 3 parts of compound (2) was used, and an image was obtained in the same manner by performing development, transfer, and fixing. Detailed results are shown in Tables 1 and 2, but Example 5
Almost the same satisfactory results were obtained. Example 7 In Example 5, instead of 2 parts of compound (1),
A developer was obtained in the same manner as in Example 5, except that 7 parts of compound (3) was used, and an image was obtained in the same manner by performing development, transfer, and fixing. The detailed results are shown in Tables 1 and 2, and almost the same satisfactory results as in Example 5 were obtained. Comparative Example 2 In Example 5, instead of 2 parts of compound (1),
A developer was obtained in the same manner as in Example 5, except that 2 parts of benzylmethyl-hexadecyl ammonium chloride was used, and an image was obtained in the same manner. At room temperature and humidity, the image density was low at 0.81 with little fog, line drawings were scattered, and solid blacks were noticeably rough. Furthermore, the above-mentioned filming phenomenon during durability and problems in the fixing process were almost the same as in Comparative Example 1, and were undesirable. When an image was obtained at 35° C. and 85%, the image density was as low as 0.72, and fogging, scattering, and roughness increased, making it unusable. Transfer efficiency was also low. When an image was obtained under conditions of 15°C and 10%, the image density was as low as 0.73, and there was severe scattering, fogging, roughness, and noticeable transfer omissions. Example 8 Styrene/butyl methacrylate (80/20) copolymer 100 parts (weight average molecular weight Mw: approximately 300,000) Copper phthalocyanine blue pigment 5 parts Low molecular weight polypropylene wax 2 parts Compound (1) 2 parts The above materials were blended After mixing well at 150
The mixture was kneaded using two rolls heated to ℃. After the kneaded material was left to cool naturally, it was roughly pulverized using a cutter mill, then pulverized using a pulverizer using jet air flow, and further classified using an air classifier to obtain a fine powder with a particle size of 5 to 20μ. . Next, 50 g of magnetic particles having a particle size of 50 to 80 μm were mixed with 100 parts of the fine powder to prepare a developer. When this developer was used to develop images using the developing method shown in Figure 1, good images with a bright blue color were obtained, and after 1500 images, the toner/carrier was 10g/50g. There was almost no change in image density even after the change in image density. To explain this developing method, in FIG. 1, 1 is an electrostatic image holder, 2 is a toner carrier, 3 is a hopper, and 5
2 is a magnetic brush with a carrier toner mixture;
58 is a toner thickness regulating blade, 50 is a fixed magnet, 6 is a developing bias, and 5 is a toner. That is, the magnetic brush 52 formed on the toner carrier 2 is circulated by rotating the toner carrier 2, takes in the toner in the hopper 3, and uniformly coats the toner 2 in a thin layer. Next, the toner carrier 2 and the electrostatic image carrier 1 are made to face each other with a gap larger than the toner layer thickness, and the toner 5 on the toner carrier 2 is caused to fly onto the electrostatic charge image on the electrostatic image carrier 1 for development. The thickness of the toner layer is controlled by the size of the magnetic brush 52, ie, the amount of magnetic particles, and the regulating blade 58. The gap between 1 and 2 may be made larger than the toner layer thickness, and a developing bias of 6 may be applied. The evaluation results of each example and comparative example are shown in Tables 1 and 2.

[Table] ○〓〓〓〓Good △〓〓〓〓Slightly poor ×〓〓〓〓Poor

〔Effect of the invention〕

The effects obtained by the present invention are as follows. (1) The amount of triboelectric charge between toner particles, between toner and carrier, or between toner and toner carrier such as a sleeve in the case of one-component development is stable, and the distribution of triboelectricity is sharp and uniform. It is a developer that can control the amount of charge to suit the developing system used. (2) The developer is capable of faithfully developing and transferring latent images, maintains its initial characteristics even when used continuously over a long period of time, and does not cause toner aggregation or change in charging characteristics. (3) A developer that can reproduce stable images that are unaffected by changes in temperature and humidity, and that can also produce images with vivid chromatic colors. (4) The developer is easy to clean, does not stain, rub or scratch the electrostatic latent image surface, has excellent fixing properties, and does not cause any problems, especially in high-temperature offsets.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of a developing device to which the positively chargeable toner according to the present invention can be applied. 1... Electrostatic image carrier, 2... Toner carrier, 5
... Toner, 50 ... Magnet, 52 ... Magnetic brush, 58 ... Regulation blade.

Claims (1)

[Claims] 1. A toner for developing an electrostatic image, comprising a triazine condensate having at least two or more triazine rings.