High-stability carbon powder as well as preparation method and application thereof

Abstract

The invention relates to the technical field of printing materials, in particular to high-stability carbon powder as well as a preparation method and application thereof. The carbon powder comprises the following components in parts by mass: 60-70 parts of modified styrene-acrylic resin, 10-12 parts of carbon black, 5-6 parts of a charge control agent, 5-6 parts of a silane coupling agent, 18-22 parts of magnetic iron oxide, 2-4 parts of a lubricant and 2-4 parts of a plasticizer, the carbon powder disclosed by the invention is good in stability under high-temperature and high-humidity storage conditions, the problems of caking, charge attenuation and image blurring are effectively prevented, and the carbon powder also has a relatively wide melting point range, so that the continuity of printing operation and the consistency of output quality are ensured.

Description

Technical Field

[0001] This application relates to the technical field of printing materials, and in particular to a highly stable toner, its preparation method, and its application. Background Technology

[0002] Toner (also known as ink powder), as a key printing consumable in laser printers, mainly consists of components such as resin, colorant, and charge conditioner. During electrostatic copying or laser printing, it transfers images to the paper surface through thermal melting.

[0003] Some toners exhibit clumping after short-term storage in environments with high humidity and / or significant temperature fluctuations. This not only damages the internal components of the developing chamber, thus affecting image quality, but also significantly shortens the lifespan of the developing chamber.

[0004] Furthermore, toner with a narrow melting point range can easily lead to unstable print quality. For example, during a printing job, temperature changes may cause uneven melting of the toner, resulting in spots, blurring, or poor fixing of the image.

[0005] Therefore, this application provides a highly stable toner, its preparation method, and its application. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this application provides a highly stable toner, its preparation method, and its application. The toner exhibits good stability under high temperature and high humidity storage conditions, effectively preventing agglomeration, charge decay, and image blurring. Furthermore, the toner has a wide melting point range, thereby ensuring the continuity of printing operations and the consistency of output quality.

[0007] The technical solution adopted by this application to solve its technical problem is:

[0008] According to a first aspect of this application, a highly stable toner is provided, comprising the following components in parts by weight:

[0009] Modified styrene-acrylic resin 60-70 parts, carbon black 10-12 parts, charge regulator 5-6 parts, silane coupling agent 5-6 parts, magnetic iron oxide 18-22 parts, lubricant 2-4 parts, plasticizer 2-4 parts;

[0010] The modified styrene-acrylic resin comprises the following raw materials:

[0011] The mixture comprises hard monomers, soft monomers, functional monomers, initiators, emulsifiers, and dispersants, wherein the mass ratio of hard monomers, soft monomers, functional monomers, initiators, emulsifiers, and dispersants is (71~81):(18~22):(3~5):(0.6~1.0):(1.6~2.4):(180~220).

[0012] The preparation process of the modified styrene-acrylic resin includes: mixing hard monomers, soft monomers, functional monomers, emulsifiers and dispersants to prepare a pre-emulsion; performing seed emulsion polymerization on a portion of the pre-emulsion and a portion of the initiator, and then adding the remaining pre-emulsion and the remaining initiator to carry out a polymerization reaction; after the reaction is completed, adjusting the pH to 6.5~7.0, drying and pulverizing to obtain the modified styrene-acrylic resin.

[0013] The plasticizer is tricyclohexyl citrate;

[0014] The silane coupling agent includes at least one of vinyltriethoxysilane and vinyltrimethoxysilane.

[0015] In some embodiments, the particle size Dv90 of the carbon black is 5 μm to 10 μm.

[0016] In some embodiments, the charge regulator is a quaternary ammonium salt charge regulator.

[0017] In some embodiments, the magnetic iron oxide has a particle size Dv90 of 5 μm to 10 μm.

[0018] In some implementations, the lubricant is polyethylene wax.

[0019] In some embodiments, the hard monomer includes styrene, methyl methacrylate, and isobornyl methacrylate;

[0020] The soft monomer is butyl acrylate;

[0021] The functional monomers include acrylic acid and glycidyl methacrylate;

[0022] The initiator is potassium persulfate;

[0023] The emulsifiers include polyoxyethylene octylphenol ether and sodium dodecyl sulfate;

[0024] The dispersant is water.

[0025] In some embodiments, the modified styrene-acrylic resin comprises the following components in parts by weight:

[0026] Styrene 43-48 parts, methyl methacrylate 19-22 parts, isobornyl methacrylate 9-11 parts, butyl acrylate 18-22 parts; acrylic acid 2-3 parts, glycidyl methacrylate 1-2 parts, potassium persulfate 0.6-1.0 parts, polyoxyethylene octylphenol ether 1.0-1.4 parts, sodium dodecyl sulfate 0.6-1.0 parts, water 180-220 parts.

[0027] In some embodiments, the seed emulsion polymerization of a portion of the pre-emulsion and a portion of the initiator is carried out as follows: take 1 / 4 of the pre-emulsion, add 1 / 2 of the potassium persulfate solution dropwise at 75°C, and after the addition is completed, keep warm at 75°C for 30 min to 60 min.

[0028] And / or, the remaining pre-emulsion and the remaining initiator are then added to carry out the polymerization reaction. The specific process is as follows: the remaining pre-emulsion and the remaining initiator are added dropwise to the liquid after the seed emulsion polymerization is completed. After the addition is completed, the temperature is raised to 85°C and the reaction is carried out at 85°C for 60 min to 90 min.

[0029] Secondly, this application provides a method for preparing the toner described in the first aspect, comprising the following steps:

[0030] Modified styrene-acrylic resin, carbon black, charge regulator, silane coupling agent, magnetic iron oxide, lubricant, and plasticizer are mixed according to their mass ratio, and then the mixture is melt-extruded, pulverized, and graded to obtain carbon powder.

[0031] Thirdly, an application of toner in electrostatic copying or laser printing is provided, wherein the toner includes the toner described in the first aspect or the toner prepared by the method of the second aspect.

[0032] Compared with the prior art, this application has the following beneficial effects:

[0033] The toner of this application exhibits excellent thermal stability and environmental adaptability, demonstrating good stability under high temperature and high humidity storage conditions. It effectively prevents clumping, charge decay, and image blurring, primarily due to the uniform molecular structure formed by the seed emulsion polymerization process and the reinforcing effect of the modified styrene-acrylic resin. Simultaneously, the toner possesses a wide melting point range, ensuring continuous printing operations and consistent output quality. Furthermore, the synergistic regulation of plasticizers and lubricants reduces the risk of clogging during high-speed printing. In addition, the charge regulator and silane coupling agent in the toner optimize surface electrical properties, further enhancing durability under long-term storage and extreme conditions, and preventing printing defects caused by humidity changes. Detailed Implementation

[0034] To facilitate understanding by those skilled in the art, the present application will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present application.

[0035] As used herein, “and / or” includes all combinations of any one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used herein, the singular forms “a,” “an,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. Further understanding is needed; when used in this specification, “comprising” specifies the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0036] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Further understanding is that terms, such as those defined in commonly used dictionaries, are interpreted in accordance with their meaning in the context of the relevant field and are not idealized or overly formal, unless expressly defined herein.

[0037] The exemplary invention described herein may suitably omit any one or more limiting elements, which are not specifically disclosed herein. Therefore, terms such as “comprising,” “including,” “containing,” etc., should be interpreted broadly and non-limitingly. Furthermore, the terminology used herein is for descriptive purposes without limitation, and it is unintentional to use terms that do not include any equivalent characteristics, but only to describe a subset of their characteristics; however, various modifications are possible within the scope of this application according to the claims. Therefore, while this application has been specifically disclosed through preferred embodiments and optional features, modifications disclosed herein to embody variations of this application may be noted by those skilled in the art, and such modifications and variations are considered to be within the scope of this application.

[0038] According to a first aspect of this application, a highly stable toner is provided, comprising the following components in parts by weight:

[0039] Modified styrene-acrylic resin 60-70 parts, carbon black 10-12 parts, charge regulator 5-6 parts, silane coupling agent 5-6 parts, magnetic iron oxide 18-22 parts, lubricant 2-4 parts, plasticizer 2-4 parts;

[0040] The modified styrene-acrylic resin comprises the following raw materials:

[0041] The mixture comprises hard monomers, soft monomers, functional monomers, initiators, emulsifiers, and dispersants, wherein the mass ratio of hard monomers, soft monomers, functional monomers, initiators, emulsifiers, and dispersants is (71~81):(18~22):(3~5):(0.6~1.0):(1.6~2.4):(180~220).

[0042] The preparation process of the modified styrene-acrylic resin includes: mixing hard monomers, soft monomers, functional monomers, emulsifiers and dispersants to prepare a pre-emulsion; performing seed emulsion polymerization on a portion of the pre-emulsion and a portion of the initiator, and then adding the remaining pre-emulsion and the remaining initiator to carry out a polymerization reaction; after the reaction is completed, adjusting the pH to 6.5~7.0, drying and pulverizing to obtain the modified styrene-acrylic resin.

[0043] The plasticizer is tricyclohexyl citrate;

[0044] The silane coupling agent includes at least one of vinyltriethoxysilane and vinyltrimethoxysilane.

[0045] In this technical solution, modified styrene-acrylic resin serves as the binder for the toner, firmly bonding materials such as carbon black and magnetic iron oxide to ensure excellent toner particle molding performance. Its function is to enhance the thermal stability and environmental adaptability of the toner, effectively suppressing agglomeration under high temperature and humidity conditions, while also providing a basic mechanical support structure to prevent particle breakage during printing.

[0046] Specifically, a seed emulsion polymerization process is employed: first, a pre-emulsion in a 1 / 4 ratio and an initiator in a 1 / 2 ratio are used to form seed particles, followed by the gradual addition of the remaining raw materials to initiate the polymerization reaction. This process constructs a uniform molecular structure and reduces defects in the molecular chain structure. Rigid monomer components (such as styrene) provide rigid support to the material, flexible monomer components (such as butyl acrylate) provide appropriate flexibility, and functional monomer components (such as acrylic acid) introduce active groups, thereby achieving an optimized balance between the resin's thermal stability and melt flowability.

[0047] Carbon black, as the core colorant, provides a black color effect for printed images, ensuring image density; at the same time, it works synergistically to regulate the conductivity of the toner, improving the charge transfer efficiency during the development process.

[0048] Charge regulators can optimize the charge distribution on the surface of toner, ensure charge stability during development, and prevent charge decay; at the same time, they can enhance the charge interaction between toner and carrier, reducing fly powder and background graying.

[0049] Magnetic iron oxide imparts magnetic properties to toner, ensuring its adsorption and transfer efficiency on the developing roller, which is compatible with the magnetron development mechanism of laser printing; at the same time, it helps to enhance the mechanical strength of toner particles and reduce the breakage rate during high-speed printing.

[0050] The lubricant significantly reduces the coefficient of friction between toner particles and between toner and printing components, thereby enhancing flowability and effectively reducing the risk of clogging. Simultaneously, the lubricant prevents toner from adhering to the roller surface in its molten state, ensuring a smooth fixing process.

[0051] Plasticizers are used to regulate the melting point range of toner, expanding its melting temperature range to adapt to temperature fluctuations in different printing environments. This component improves the film-forming properties of toner in the molten state, enhances fixing adhesion, and prevents image detachment. Tricyclohexyl citrate is selected because its ester groups can embed between the molecular chains of modified styrene-acrylic resin, weakening intermolecular forces and thus lowering the resin's glass transition temperature. Through synergistic action with lubricants, the melting characteristics of the toner are further regulated, the melting point range is expanded, and uneven melting caused by temperature fluctuations is avoided, ensuring high-resolution imaging results.

[0052] Vinyltriethoxysilane or vinyltrimethoxysilane are preferred silane coupling agents. The siloxane groups in their molecules can undergo hydrolysis and condense with the hydroxyl groups on the surface of inorganic components (such as magnetic Fe3O4 and carbon black); the terminal vinyl groups can undergo free radical copolymerization with the double bonds in the modified styrene-acrylic resin. This process forms an "organic-inorganic bridging structure," which can effectively reduce the interfacial tension between components, improve the compatibility between resin, carbon black, and magnetic iron oxide, reduce agglomeration, inhibit particle aggregation during storage and printing, and enhance the hydrophobic properties of the toner surface, preventing moisture absorption and clumping in high-humidity environments.

[0053] In some embodiments, the carbon black particle size Dv90 is 5~10 μm, for example, DV90 can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or any combination thereof. Controlling the carbon black particle size within the above range ensures its uniform dispersion in the modified styrene-acrylic resin, promotes the interaction between the active sites on the carbon black surface and the active groups of the modified styrene-acrylic resin, enhances interfacial bonding, effectively suppresses colorant shedding during printing, and avoids imaging spots caused by localized aggregation.

[0054] In some embodiments, the charge regulator is selected from quaternary ammonium salt compounds. Quaternary ammonium salt compounds stabilize the charge characteristics during the development process to suppress attenuation, effectively suppress dust emission and background graying, thereby optimizing the development uniformity and regulating the surface charge distribution of toner particles. At the same time, they enhance the charge interaction between toner and modified styrene-acrylic resin, ensuring good coupling with the magnetic control development mechanism of the laser printer.

[0055] Furthermore, the quaternary ammonium salt charge regulator is at least one of hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride. Both hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride contain cationic groups, which can dissociate in the system to form stable positive charge centers, promoting uniform charging of toner particles; at the same time, they can synergistically interact with silane coupling agents to optimize the surface potential of toner, adapting it to different environmental humidity conditions, maintaining charge stability, and thus ensuring print quality.

[0056] In some embodiments, the particle size Dv90 of the magnetic iron oxide is 5μm to 10μm, for example, DV90 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or any combination thereof. Matching the particle size of the magnetic iron oxide with that of the carbon black ensures its uniform dispersion in the modified styrene-acrylic resin, making the hysteresis loop characteristics of the magnetic iron oxide compatible with the developing system. This ensures that the toner responds quickly to changes in the magnetic field, achieving precise transfer and avoiding developing deviations caused by uneven distribution of the magnetic iron oxide.

[0057] In some embodiments, the lubricant is polyethylene wax, with CAS number 9002-88-4. Polyethylene wax has low surface energy and can form a lubricating film on the surface of toner particles, effectively reducing the van der Waals forces between particles. Furthermore, the polyethylene wax and plasticizer have a synergistic effect, significantly reducing the system viscosity during the toner melting stage and inhibiting particle adhesion after cooling, thereby improving the continuity of the printing process.

[0058] In some embodiments, the hard monomer includes styrene, methyl methacrylate, and isobornyl methacrylate; the soft monomer is butyl acrylate; the functional monomer includes acrylic acid and glycidyl methacrylate; the initiator is potassium persulfate; the emulsifier includes polyoxyethylene octylphenol ether and sodium dodecyl sulfate; and the dispersant is water.

[0059] In some examples, the modified styrene-acrylic resin comprises the following components in parts by weight:

[0060] 71-81 parts hard monomer, 18-22 parts soft monomer, 3-5 parts functional monomer, 0.6-1.0 parts initiator, 1.6-2.4 parts emulsifier, and 180-220 parts dispersant;

[0061] For example, the hard monomers include 43-48 parts styrene, 19-22 parts methyl methacrylate, and 9-11 parts isobornyl methacrylate. In addition, the hard monomers (including styrene, methyl methacrylate, and isobornyl methacrylate) provide rigid skeleton support for the modified styrene-acrylic resin, effectively improving the thermal stability of the toner. They also work synergistically with the soft monomers to regulate the melt flow balance, thereby suppressing the tendency to agglomerate under high temperature and high humidity conditions and avoiding particle breakage during the printing process.

[0062] For example, the soft monomer is butyl acrylate in a mass fraction of 18 to 22 parts; the soft monomer provides moderate flexibility and works synergistically with the hard monomer to regulate the balance between the resin’s thermal stability and melt flowability, ensuring the fluidity of the toner when it melts, which is beneficial for fixing and does not damage the rigid support structure.

[0063] For example, the functional monomers include 2-3 parts acrylic acid and 1-2 parts glycidyl methacrylate. By introducing active groups (including carboxyl groups and epoxy groups) through functional monomers (such as acrylic acid and glycidyl methacrylate), the interfacial bonding force between the resin and components such as carbon black and magnetic iron oxide can be significantly enhanced, thereby improving compatibility, inhibiting agglomeration, and ultimately improving the overall performance of the resin.

[0064] For example, the initiator is potassium persulfate with a mass fraction of 0.6 to 1.0 parts; the initiator can initiate free radical polymerization, start seed emulsion polymerization and subsequent polymerization processes, form the molecular chain structure of modified styrene-acrylic resin, and ensure the smooth progress of the polymerization reaction.

[0065] For example, the emulsifier contains 1.0-1.4 parts of polyoxyethylene octylphenol ether and 0.6-1.0 parts of sodium dodecyl sulfate. The emulsifier can stabilize the emulsion system, prevent monomer droplet aggregation, promote uniform dispersion of the pre-emulsion, ensure uniform resin particle size during polymerization, and avoid agglomeration.

[0066] For example, the dispersant is water with a mass fraction of 180-220 parts. As a medium for the polymerization reaction, the dispersant dissolves emulsifiers, initiators, and other components, disperses monomers to form a pre-emulsion, provides the reaction environment, and ensures the smooth progress of emulsion polymerization.

[0067] Specifically, the modified styrene-acrylic resin comprises the following components in parts by weight:

[0068] Styrene 43-48 parts, methyl methacrylate 19-22 parts, isobornyl methacrylate 9-11 parts, butyl acrylate 18-22 parts; acrylic acid 2-3 parts, glycidyl methacrylate 1-2 parts, potassium persulfate 0.6-1.0 parts, polyoxyethylene octylphenol ether 1.0-1.4 parts, sodium dodecyl sulfate 0.6-1.0 parts, water 180-220 parts.

[0069] In some embodiments, the seed emulsion polymerization of a portion of the pre-emulsion and a portion of the initiator is carried out as follows: take 1 / 4 of the pre-emulsion, add 1 / 2 of the potassium persulfate solution dropwise at 75°C, and after the addition is completed, keep warm at 75°C for 30-60 minutes.

[0070] In some embodiments, the remaining pre-emulsion and the remaining initiator are then added to carry out the polymerization reaction. The specific process is as follows: the remaining pre-emulsion and the remaining initiator are added dropwise to the liquid after the seed emulsion polymerization is completed. After the addition is completed, the temperature is raised to 85°C and the reaction is carried out at 85°C for 60-90 minutes.

[0071] The preparation method of the modified styrene-acrylic resin described above in this application includes the following steps:

[0072] Step S11: Preparation of pre-emulsion

[0073] Add 140 parts of dispersion medium (deionized water), 1.0~1.4 parts of polyoxyethylene octylphenol ether OP-10, and 0.6~1.0 parts of sodium dodecyl sulfate to the first reactor and stir at 300 rpm for 10 min until completely dissolved;

[0074] Add 43-48 parts of styrene, 19-22 parts of methyl methacrylate, 9-11 parts of isobornyl methacrylate, 18-22 parts of butyl acrylate, 2-3 parts of acrylic acid, and 1-2 parts of glycidyl methacrylate in sequence. Increase the stirring speed to 500 rpm and ultrasonically disperse for 15 min to form a homogeneous pre-emulsion for later use.

[0075] Step S12, Seed emulsion polymerization

[0076] Add 40-80 parts of deionized water to the second reactor, purge with nitrogen three times to remove oxygen and prevent polymerization, and heat to 75°C.

[0077] Add 1 / 4 of the pre-emulsion to the second reactor and stir at 400 rpm; add 1 / 2 of the potassium persulfate solution (0.6-1.0 parts of potassium persulfate dissolved in 10 parts of deionized water) dropwise for 30 min, and keep warm for 30 min after the addition is complete.

[0078] Step S13, Monomer addition and polymerization

[0079] Stable blue light was observed in the system. The temperature was maintained at 75℃, and the remaining 3 / 4 of the pre-emulsion and the remaining 1 / 2 of the potassium persulfate solution were added dropwise over a period of 120 min. After the addition was completed, the temperature was raised to 85℃ and kept at that temperature for 60 min.

[0080] After the heat preservation is completed, the temperature is lowered to 50℃, the pH is adjusted to 6.5~7.0 with 10% ammonia water, and stirred for 30 minutes to obtain modified styrene-acrylic latex.

[0081] Step S14, Drying

[0082] The modified styrene-acrylic latex was poured into a petri dish and dried in a vacuum drying oven at 60°C for 24 hours to remove moisture. The dried resin was then pulverized and passed through a 200-mesh sieve to obtain powdered modified styrene-acrylic resin.

[0083] The modified styrene-acrylic resin prepared in this application has the following characteristics:

[0084] (1) Firmly bond components such as carbon black and magnetic iron oxide to ensure that the carbon powder particles have excellent forming properties;

[0085] (2) Enhance the thermal stability and environmental adaptability of toner, and effectively suppress the tendency of agglomeration under high temperature and high humidity conditions;

[0086] (3) Provide a mechanical support structure to prevent mechanical damage to the particles during the printing process;

[0087] (4) A uniform molecular structure is constructed through seed emulsion polymerization, which works in conjunction with rigid monomers (such as styrene), flexible monomers (such as butyl acrylate) and functional monomers to achieve an optimized balance between thermal stability and melt flowability.

[0088] (5) It produces a synergistic effect with silane coupling agents, improves the compatibility of multiple components, inhibits agglomeration, and ensures the stability of toner performance.

[0089] Secondly, this application provides a method for preparing the toner described in the first aspect, comprising the following steps:

[0090] Modified styrene-acrylic resin, carbon black, charge regulator, silane coupling agent, magnetic iron oxide, lubricant, and plasticizer are mixed according to their mass ratio, and then the mixture is melt-extruded, pulverized, and graded to obtain carbon powder.

[0091] In some embodiments, the method for preparing the toner includes the following steps:

[0092] S100, Raw material pretreatment

[0093] (1) Drying treatment: The modified styrene-acrylic resin (60~70 parts) was placed in a vacuum drying oven at 60℃ (vacuum degree -0.09MPa) and dried for 24h to reduce its moisture content to ≤0.5% to prevent clumping during storage; the carbon black (10~12 parts, Dv90=5~10μm) and magnetic iron oxide (18~22 parts, Dv90=5~10μm) were placed in a forced-air drying oven at 80℃ and dried for 4h to remove surface adsorbed water.

[0094] (2) Pre-dispersion: Place 40% (5-6 parts, vinyltriethoxysilane) of the total mass of dried carbon black and silane coupling agent in a high-speed disperser (3000 rpm) and disperse for 15 min to form a carbon black-silane pre-dispersion; disperse the magnetic iron oxide and the remaining 60% of the silane coupling agent in the same way, collect and set aside.

[0095] S200, Premix

[0096] The pretreated modified styrene-acrylic resin, carbon black-silane predispersant, magnetic iron oxide-silane predispersant, charge regulator, lubricant, and plasticizer were added to a high-speed mixer. The stirring speed was set to 1500 rpm and the mixing temperature to 40℃, and the mixture was continuously mixed for 30 minutes to obtain a uniform powder.

[0097] S300, melt extrusion

[0098] (1) Equipment and parameters: A twin-screw extruder (screw diameter 30mm, length-to-diameter ratio 40:1) is used. Five temperature zones are set from the feed port to the discharge port. The temperatures are as follows: feed zone 110-115℃, compression zone 130-135℃, melting zone 150-155℃, homogenization zone 143-145℃, and discharge zone 140-143℃. The main machine speed is 120rpm, the feeding rate is 8kg / h, and the vacuum degree is -0.08MPa.

[0099] (2) Operation: The premixed powder is added to the feeder at a uniform speed, and after being melted and mixed by the twin-screw extruder, it is extruded into strips through the die head (orifice diameter 3mm) to ensure that the surface of the extruded material is smooth and free of bubbles.

[0100] S400 Cooling and Coarse Grinding

[0101] (1) Cooling and shaping: The extruded strip material is immediately put into a water cooling tank (water temperature 25℃, water flow rate 0.5m / s) to cool to room temperature (≤30℃) to prevent the material from sticking together; after cooling, a blower (wind speed 5m / s) is used to remove surface moisture.

[0102] (2) Coarse crushing: The cooled strip material is fed into a hammer crusher (screen mesh size 5mm), the rotor speed is set to 2000rpm, and it is crushed into coarse particles with a particle size of 2~5mm and collected for later use.

[0103] S500, micronized

[0104] Coarse particles were finely pulverized using an air jet mill (compressed air pressure 0.8 MPa, airflow temperature 25℃). The classifying wheel speed was set to 8000 rpm, and the volumetric median particle size (Dv50) of the pulverized particles was controlled to be 8~12 μm. The fine powder was collected by a cyclone separator, and the exhaust gas was used to recover the fine powder via a bag filter.

[0105] S600, Classification

[0106] The finely pulverized powder is fed into a turbine classifier, with the classifying wheel speed set to 10,000 rpm. Excessively coarse and excessively fine particles are separated, yielding carbon powder with a particle size distribution of Dv50 = 8~12 μm and Dv90 ≤ 15 μm.

[0107] Understandably, DV10 is the particle size at which the cumulative volume distribution reaches 10%, meaning that 10% of the particles have a volume smaller than this value, reflecting the proportion of fine particles.

[0108] DV50 is the particle size (median diameter) when the cumulative volume distribution reaches 50%, representing the average size of the particle population;

[0109] DV90 is the particle size at which the cumulative volume distribution reaches 90%, meaning that 90% of the particles have a volume smaller than this value, reflecting the proportion of coarse particles.

[0110] In a third aspect, there is provided an application of toner in electrostatic copying or laser printing, wherein the toner comprises the toner described in the first aspect or the toner prepared by the preparation method described in the second aspect.

[0111] For example, when applied in an electrostatic copying device or a laser printer, the toner has excellent thermal stability and environmental adaptability characteristics, good stability under high-temperature and high-humidity storage conditions, effectively preventing problems such as caking, charge decay, and image blurring. The toner also has a relatively wide melting point range, which is conducive to achieving uniform melting and rapid fixing during the printing process, reducing problems such as poor fixing or thermal offset caused by temperature fluctuations, and at the same time ensuring that toner particles form a firm and high-resolution image on the surface of the printing medium, significantly reducing the occurrence rate of printing defects such as ghosting and background gray.

[0112] Through the following preparation examples, examples, and comparative examples, a high-stability toner and its preparation method and application of the present application will be further described.

[0113] Testing methods and equipment

[0114] 1. Caking rate test

[0115] Take 10 g of toner and place it in a constant temperature and humidity box at 60 °C and 85% RH for 72 h. After taking it out, pass it through a 300-mesh standard sieve, weigh the mass of the residual caked matter on the sieve, and calculate the caking rate (caking rate = mass of material on the sieve / 10 g × 100%). A caking rate ≤ 5% is considered qualified.

[0116] 2. Charge stability

[0117] Use a blowing method charge quantity measuring instrument to measure the initial charge quantity of the toner (in an environment of 23 °C / 50% RH) and the charge quantity after storing at 40 °C and 85% RH for 72 h, and calculate the charge quantity change rate;

[0118] Change rate = (charge quantity after storage - initial charge quantity) / initial charge quantity × 100%. A change rate ≤ 10% is considered qualified.

[0119] 3. Thermal stability

[0120] Use differential scanning calorimetry (DSC) to heat from 25 °C to 200 °C at a heating rate of 10 °C / min, record the starting temperature and ending temperature of toner melting, and calculate the melting point range. A range ≥ 20 °C meets the requirement of a wide melting point;

[0121] 4. Print quality stability

[0122] Use a laser printer to continuously print 3000 standard test pages at 1200 dpi, and use an image analyzer to measure the number of dots in the initial and 3000-page images. A dot number ≤ 3 dots / page is considered qualified.

[0123] 5. Image density attenuation rate

[0124] Print a standard test page at 1200 dpi using a laser printer to obtain the initial printed image; use a friction tester with a 500g load to rub the printed image area back and forth 50 times; compare the image state before and after friction and calculate the image density attenuation rate. Image density attenuation rate = (initial image density − image density after friction) / initial image density * 100%.

[0125] Preparation Example 1:

[0126] The preparation method of modified styrene-acrylic resin includes the following steps:

[0127] Step S11: Preparation of pre-emulsion

[0128] Add 140g of dispersion medium (deionized water), 1.2g of polyoxyethylene octylphenol ether OP-10, and 0.8g of sodium dodecyl sulfate to the first reactor and stir at 300rpm for 10min until completely dissolved.

[0129] Add 45g of styrene, 20g of methyl methacrylate, 10g of isobornyl methacrylate, 20g of butyl acrylate, 2.5g of acrylic acid, and 1.5g of glycidyl methacrylate in sequence. Increase the stirring speed to 500rpm and sonicate for 15min to form a homogeneous pre-emulsion for later use.

[0130] Step S12, Seed emulsion polymerization

[0131] Add 60g of deionized water to the second reactor, purge with nitrogen three times to remove oxygen and prevent polymerization, and heat to 75℃.

[0132] Add 1 / 4 of the pre-emulsion to the second reactor and stir at 400 rpm; add 1 / 2 of the potassium persulfate solution (0.8 g of potassium persulfate dissolved in 10 g of deionized water) dropwise for 30 min, and keep warm for 30 min after the addition is complete.

[0133] Step S13, Monomer addition and polymerization

[0134] Stable blue light was observed in the system. The temperature was maintained at 75℃, and the remaining 3 / 4 of the pre-emulsion and the remaining 1 / 2 of the potassium persulfate solution were added dropwise over a period of 120 min. After the addition was completed, the temperature was raised to 85℃ and kept at that temperature for 60 min.

[0135] After the heat preservation is completed, the temperature is lowered to 50℃, the pH is adjusted to 6.8 with 10% ammonia water, and stirred for 30 minutes to obtain modified styrene-acrylic latex.

[0136] Step S14, Drying

[0137] The modified styrene-acrylic latex was poured into a petri dish and dried in a vacuum drying oven at 60°C for 24 hours to remove moisture. The dried resin was then pulverized and passed through a 200-mesh sieve to obtain powdered modified styrene-acrylic resin.

[0138] Preparation Example 2:

[0139] The preparation method of modified styrene-acrylic resin includes the following steps:

[0140] Step S11: Preparation of pre-emulsion

[0141] Add 140g of dispersion medium (deionized water), 1.0g of polyoxyethylene octylphenol ether OP-10, and 0.6g of sodium dodecyl sulfate to the first reactor and stir at 300rpm for 10min until completely dissolved.

[0142] Add 43g of styrene, 19g of methyl methacrylate, 9g of isobornyl methacrylate, 18g of butyl acrylate, 2g of acrylic acid, and 1g of glycidyl methacrylate in sequence. Increase the stirring speed to 500rpm and ultrasonically disperse for 15min to form a homogeneous pre-emulsion for later use.

[0143] Step S12, Seed emulsion polymerization

[0144] Add 40g of deionized water to the second reactor, purge with nitrogen three times to remove oxygen and prevent polymerization, and heat to 75℃.

[0145] Add 1 / 4 of the pre-emulsion to the second reactor and stir at 400 rpm; add 1 / 2 of the potassium persulfate solution (0.6 g of potassium persulfate dissolved in 10 g of deionized water) dropwise for 30 min, and keep warm for 30 min after the addition is complete.

[0146] Step S13, Monomer addition and polymerization

[0147] Stable blue light was observed in the system. The temperature was maintained at 75℃, and the remaining 3 / 4 of the pre-emulsion and the remaining 1 / 2 of the potassium persulfate solution were added dropwise over a period of 120 min. After the addition was completed, the temperature was raised to 85℃ and kept at that temperature for 60 min.

[0148] After the heat preservation is completed, the temperature is lowered to 50℃, the pH is adjusted to 6.5 with 10% ammonia water, and stirred for 30 minutes to obtain modified styrene-acrylic latex.

[0149] Step S14, Drying

[0150] The modified styrene-acrylic latex was poured into a petri dish and dried in a vacuum drying oven at 60°C for 24 hours to remove moisture. The dried resin was then pulverized and passed through a 200-mesh sieve to obtain powdered modified styrene-acrylic resin.

[0151] Preparation Example 3:

[0152] The preparation method of modified styrene-acrylic resin includes the following steps:

[0153] Step S11: Preparation of pre-emulsion

[0154] Add 140g of dispersion medium (deionized water), 1.4g of polyoxyethylene octylphenol ether OP-10, and 1.0g of sodium dodecyl sulfate to the first reactor and stir at 300rpm for 10min until completely dissolved.

[0155] Add 48g of styrene, 22g of methyl methacrylate, 11g of isobornyl methacrylate, 22g of butyl acrylate, 3g of acrylic acid, and 2g of glycidyl methacrylate in sequence. Increase the stirring speed to 500rpm and ultrasonically disperse for 15min to form a homogeneous pre-emulsion for later use.

[0156] Step S12, Seed emulsion polymerization

[0157] Add 80g of deionized water to the second reactor, purge with nitrogen three times to remove oxygen and prevent polymerization, and heat to 75℃.

[0158] Add 1 / 4 of the pre-emulsion to the second reactor and stir at 400 rpm; add 1 / 2 of the potassium persulfate solution (1.0 g of potassium persulfate dissolved in 10 g of deionized water) dropwise for 30 min, and keep warm for 30 min after the addition is complete.

[0159] Step S13, Monomer addition and polymerization

[0160] Stable blue light was observed in the system. The temperature was maintained at 75℃, and the remaining 3 / 4 of the pre-emulsion and the remaining 1 / 2 of the potassium persulfate solution were added dropwise over a period of 120 min. After the addition was completed, the temperature was raised to 85℃ and kept at that temperature for 60 min.

[0161] After the heat preservation is completed, the temperature is lowered to 50℃, the pH is adjusted to 7.0 with 10% ammonia water, and stirred for 30 minutes to obtain modified styrene-acrylic latex.

[0162] Step S14, Drying

[0163] The modified styrene-acrylic latex was poured into a petri dish and dried in a vacuum drying oven at 60°C for 24 hours to remove moisture. The dried resin was then pulverized and passed through a 200-mesh sieve to obtain powdered modified styrene-acrylic resin.

[0164] Preparation Example 4

[0165] It is basically the same as the preparation example 1; the difference is that methyl methacrylate is not added in step S11.

[0166] Preparation Example 5

[0167] It is basically the same as the preparation example 1; the difference is that isobornyl methacrylate is not added in step S11.

[0168] Preparation Example 6

[0169] It is basically the same as the preparation example 1; the difference is that glycidyl methacrylate is not added in step S11.

[0170] Example 1

[0171] Toner, comprising the following components in parts by weight:

[0172] 65 parts modified styrene-acrylic resin, 11 parts carbon black, 5.5 parts charge regulator, 5.5 parts silane coupling agent, 20 parts magnetic iron oxide, 3 parts lubricant, and 3 parts plasticizer;

[0173] Wherein: the modified styrene-acrylic resin was from Preparation Example 1; the particle size Dv90 of the carbon black was 8 μm; the Dv90 of the magnetic iron oxide was 8 μm;

[0174] The charge regulator is hexadecyltrimethylammonium bromide;

[0175] The silane coupling agent is vinyltriethoxysilane;

[0176] The lubricant is polyethylene wax (CAS No. 9002-88-4).

[0177] The plasticizer is tricyclohexyl citrate.

[0178] The above-mentioned method for preparing toner includes the following steps:

[0179] S100, Raw material pretreatment

[0180] (1) Drying treatment: The modified styrene-acrylic resin was placed in a vacuum drying oven at 60℃ (vacuum degree -0.09MPa) for 24h to reduce its moisture content to ≤0.5% to prevent clumping during storage; carbon black and magnetic iron oxide were placed in a forced-air drying oven at 80℃ for 4h to remove surface adsorbed water.

[0181] (2) Pre-dispersion: Place 40% of the total mass of dried carbon black and silane coupling agent in a high-speed disperser (3000 rpm) and disperse for 15 min to form a carbon black-silane pre-dispersion; disperse the magnetic iron oxide and the remaining 60% of the silane coupling agent in the same way, collect and set aside.

[0182] S200, Premix

[0183] The pretreated modified styrene-acrylic resin, carbon black-silane predispersant, magnetic iron oxide-silane predispersant, charge regulator, lubricant, and plasticizer were added to a high-speed mixer. The stirring speed was set to 1500 rpm and the mixing temperature to 40℃, and the mixture was continuously mixed for 30 minutes to obtain a uniform powder.

[0184] S300, melt extrusion

[0185] (1) Equipment and parameters: A twin-screw extruder (screw diameter 30mm, length-to-diameter ratio 40:1) is used. Five temperature zones are set from the feed port to the discharge port. The temperatures are as follows: feed zone 115℃, compression zone 130℃, melting zone 150℃, homogenization zone 145℃, and discharge zone 140℃. The main machine speed is 120rpm, the feeding rate is 8kg / h, and the vacuum degree is -0.08MPa.

[0186] (2) Operation: The premixed powder is added to the feeder at a uniform speed, and after being melted and mixed by the twin-screw extruder, it is extruded into strips through the die head (orifice diameter 3mm) to ensure that the surface of the extruded material is smooth and free of bubbles.

[0187] S400 Cooling and Coarse Grinding

[0188] (1) Cooling and shaping: The extruded strip material is immediately put into a water cooling tank (water temperature 25℃, water flow rate 0.5m / s) to cool to room temperature (≤30℃) to prevent the material from sticking together; after cooling, a blower (wind speed 5m / s) is used to remove surface moisture.

[0189] (2) Coarse crushing: The cooled strip material is fed into a hammer crusher (screen mesh size 5mm), the rotor speed is set to 2000rpm, and it is crushed into coarse particles with a particle size of 5mm and collected for later use.

[0190] S500, micronized

[0191] Coarse particles were finely pulverized using an air jet mill (compressed air pressure 0.8 MPa, airflow temperature 25℃). The classifying wheel speed was set to 8000 rpm, and the volumetric median particle size (Dv50) of the pulverized particles was controlled to be 8~12 μm. The fine powder was collected by a cyclone separator, and the exhaust gas was used to recover the fine powder via a bag filter.

[0192] S600, Classification

[0193] The finely pulverized powder is fed into a turbine classifier, with the classifying wheel speed set to 10,000 rpm. Excessively coarse and excessively fine particles are separated, ultimately yielding carbon powder with a particle size distribution of Dv50 = 10 μm and Dv90 = 15 μm.

[0194] Example 2

[0195] Toner, comprising the following components in parts by weight:

[0196] 60 parts modified styrene-acrylic resin, 10 parts carbon black, 5 parts charge regulator, 5 parts silane coupling agent, 18 parts magnetic iron oxide, 2 parts lubricant, and 2 parts plasticizer.

[0197] Wherein: the modified styrene-acrylic resin was from Preparation Example 2; the particle size Dv90 of the carbon black was 5 μm; the Dv90 of the magnetic iron oxide was 5 μm;

[0198] The charge regulator is hexadecyltrimethylammonium bromide;

[0199] The silane coupling agent is vinyltriethoxysilane;

[0200] The lubricant is polyethylene wax (CAS No. 9002-88-4).

[0201] The plasticizer is tricyclohexyl citrate.

[0202] The preparation method of the toner is the same as in Example 1;

[0203] Example 3

[0204] Toner, comprising the following components in parts by weight:

[0205] 70 parts modified styrene-acrylic resin, 12 parts carbon black, 6 parts charge regulator, 6 parts silane coupling agent, 22 parts magnetic iron oxide, 4 parts lubricant, and 4 parts plasticizer;

[0206] Wherein: the modified styrene-acrylic resin was from Preparation Example 3; the particle size Dv90 of the carbon black was 10 μm; the Dv90 of the magnetic iron oxide was 10 μm;

[0207] The charge regulator is hexadecyltrimethylammonium bromide;

[0208] The silane coupling agent is vinyltriethoxysilane;

[0209] The lubricant is polyethylene wax (CAS No. 9002-88-4).

[0210] The plasticizer is tricyclohexyl citrate.

[0211] The preparation method of the toner is the same as in Example 1;

[0212] Example 4

[0213] Toner, comprising the following components in parts by weight:

[0214] 62 parts modified styrene-acrylic resin, 11 parts carbon black, 5 parts charge regulator, 5 parts silane coupling agent, 19 parts magnetic iron oxide, 2 parts lubricant, and 3 parts plasticizer.

[0215] Wherein: the modified styrene-acrylic resin was from Preparation Example 1; the particle size Dv90 of the carbon black was 6 μm; the Dv90 of the magnetic iron oxide was 6 μm;

[0216] The charge control agent includes hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride, and the mass ratio of hexadecyltrimethylammonium bromide to dodecyldimethylbenzylammonium chloride is 1:1;

[0217] The silane coupling agent includes vinyltriethoxysilane and vinyltrimethoxysilane, and the mass ratio of vinyltriethoxysilane to vinyltrimethoxysilane is 1:1;

[0218] The lubricant is polyethylene wax (CAS No. 9002-88-4).

[0219] The plasticizer is tricyclohexyl citrate.

[0220] The preparation method of the toner is the same as in Example 1;

[0221] Example 5

[0222] Toner, comprising the following components in parts by weight:

[0223] 68 parts modified styrene-acrylic resin, 12 parts carbon black, 5.5 parts charge regulator, 6 parts silane coupling agent, 21 parts magnetic iron oxide, 4 parts lubricant, and 3 parts plasticizer;

[0224] Wherein: the modified styrene-acrylic resin was from Preparation Example 1; the particle size Dv90 of the carbon black was 9 μm; the Dv90 of the magnetic iron oxide was 9 μm;

[0225] The charge control agent includes hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride, and the mass ratio of hexadecyltrimethylammonium bromide to dodecyldimethylbenzylammonium chloride is 1:1;

[0226] The silane coupling agent includes vinyltriethoxysilane and vinyltrimethoxysilane, and the mass ratio of vinyltriethoxysilane to vinyltrimethoxysilane is 1:1;

[0227] The lubricant is polyethylene wax (CAS No. 9002-88-4).

[0228] The plasticizer is tricyclohexyl citrate.

[0229] The preparation method of the toner is the same as in Example 1.

[0230] Comparative Example 1

[0231] The modified styrene-acrylic resin used in this comparative example was from Preparation Example 4, and the remaining conditions were the same as in Example 1.

[0232] Comparative Example 2

[0233] The modified styrene-acrylic resin used in this comparative example was from Preparation Example 5, and the remaining conditions were the same as in Example 1.

[0234] Comparative Example 3

[0235] The modified styrene-acrylic resin used in this comparative example was from Preparation Example 6, and the remaining conditions were the same as in Example 1.

[0236] Comparative Example 4

[0237] The modified styrene-acrylic resin used in this comparative example, CAS No.: 9003-54-7, is obtained by polymerizing styrene (St) and acrylonitrile (AN).

[0238] Comparative Example 5

[0239] In this comparative example, the carbon black particle size Dv90 was 25 μm, and the other conditions were the same as in Example 1.

[0240] Comparative Example 6

[0241] In this comparative example, the particle size Dv90 of the magnetic iron oxide was 25 μm, and the other conditions were the same as in Example 1.

[0242] Comparative Example 7

[0243] In this comparative example, the charge regulator was methyltrioctylammonium chloride, and the other conditions were the same as in Example 1.

[0244] Comparative Example 8

[0245] In this comparative example, the total number of silane coupling agents was 1 part, and the other conditions were the same as in Example 1.

[0246] Comparative Example 9

[0247] In this comparative example, the total number of silane coupling agents was 12 parts, and the other conditions were the same as in Example 1.

[0248] Comparative Example 10

[0249] In this comparative example, the silane coupling agent was γ-aminopropyltriethoxysilane, and the other conditions were the same as in Example 1.

[0250] Comparative Example 11

[0251] In this comparative example, the lubricant was petroleum wax, and the other conditions were the same as in Example 1.

[0252] Comparative Example 12

[0253] In this comparative example, the plasticizer was dicyclohexyl phthalate, and the other conditions were the same as in Example 1.

[0254] Comparative Example 13

[0255] In this comparative example, the amount of plasticizer was 0.4 parts, and the other conditions were the same as in Example 1.

[0256] Comparative Example 14

[0257] In this comparative example, the amount of plasticizer was 12 parts, and the other conditions were the same as in Example 1.

[0258] The examples and comparative examples were tested according to the test methods described above, and the test results are detailed in Table 1.

[0259] Table 1

[0260]

[0261] Referring to Table 1, the agglomeration rate of Examples 1-5 was all between 1.7% and 2.3% (≤5%, qualified), the charge change rate was between 2.5% and 3.2% (≤10%, qualified), the melting point range was between 29℃ and 31℃ (≥20℃, meeting the wide melting point requirement), the number of spots was only 1 to 2 per page (≤3 per page, qualified), and the image density attenuation rate was as low as 1.15% to 1.42%. Therefore, by controlling the composition of the toner (modified styrene-acrylic resin monomer composition, filler particle size, and additive type) and its dosage within the scope of this application, the toner can simultaneously possess excellent anti-agglomeration properties, charge stability, wide melting point characteristics, and print quality stability, effectively adapting to high-temperature and high-humidity storage environments and continuous printing requirements.

[0262] Comparative Examples 1-3: Comparative Example 1 lacked the hard monomer methyl methacrylate, Comparative Example 2 lacked the hard monomer isobornyl methacrylate, and Comparative Example 3 lacked the functional monomer glycidyl methacrylate. All other conditions were the same as in Example 1. Table 1 shows that the agglomeration rate of Comparative Examples 1-3 increased sharply to 8.6%~10.5% (unacceptable), the charge change rate reached 15.3%~18.2% (unacceptable), the melting point range narrowed to 16℃~18℃ (<20℃, not meeting the wide melting point requirement), the number of spots increased to 5~7 per page, and the image density attenuation rate increased to 4.8%~5.6%. This indicates that the hard monomers (styrene, methyl methacrylate, isobornyl methacrylate) of the modified styrene-acrylic resin jointly construct the rigid framework of the resin, while the functional monomer (glycidyl methacrylate) enhances the interfacial bonding between the resin and the filler. The absence of any monomer will disrupt the uniformity and compatibility of the resin molecular structure, leading to a significant decrease in toner thermal stability, charge stability, and printing performance.

[0263] Comparative Example 4: Table 1 shows that the agglomeration rate of Comparative Example 4 reached 12.3% (exceeding the acceptable threshold), the charge change rate was as high as 22.5% (exceeding the acceptable threshold), the melting point range was only 16℃, the number of spots reached 8 per page, and the image density attenuation rate was 6.8%. All performance indicators of Comparative Example 4 were significantly inferior to those of Examples 1-5. This indicates that the modified styrene-acrylic resin (a specific combination of hard / soft / functional monomers) prepared by seed emulsion polymerization has a more uniform molecular structure, better thermal stability, and better component compatibility than ordinary styrene-acrylic resin, and can effectively suppress agglomeration and charge attenuation phenomena.

[0264] Comparative Examples 5-6: The agglomeration rate of Comparative Examples 5-6 was 11.7%~12.1%, the charge change rate was 19.8%~20.5%, the melting point range was 22℃, the number of spots was 7 / page, and the image density attenuation rate was 6.3%~6.5%. These results indicate that when the filler particle size is too large, it is difficult to disperse uniformly in the modified styrene-acrylic resin, easily forming local agglomerates, disrupting the uniformity of the toner system, and leading to a decrease in anti-agglomeration properties and charge stability. However, the 5μm~10μm particle size range specified in this application ensures a tight bond between the filler and the resin, guaranteeing the overall performance stability of the toner.

[0265] Comparative Example 7: Methyltrioctylammonium chloride (not a quaternary ammonium salt charge regulator of this application) was used instead of hexadecyltrimethylammonium bromide, and the other conditions were the same as in Example 1. Table 1 shows that the agglomeration rate of Comparative Example 7 was 7.8%, the charge change rate was 14.6%, the melting point range was 24°C, the number of spots was 5 per page, and the image density decay rate was 4.5%. These results indicate that the quaternary ammonium salt charge regulators such as hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride selected in this application can more accurately control the surface charge distribution of toner and reduce charge decay during storage; while other types of charge regulators cannot be adapted to the toner system of this application, resulting in reduced charge stability and anti-agglomeration properties.

[0266] Comparative Examples 8-9: The amounts of silane coupling agent were 1 part (Comparative Example 8, below the scope of this application) and 12 parts (Comparative Example 9, above the scope of this application), respectively, deviating from the range of 5-6 parts of this application. Other conditions were consistent with Example 1. Table 1 shows that Comparative Example 8 had an agglomeration rate of 13.5% and a charge change rate of 21.3%, while Comparative Example 9 had an agglomeration rate of 14.2% and a charge change rate of 23.1%. Both performances exceeded the acceptable threshold, and the number of spots and the decay rate were inferior to those of the examples. This phenomenon indicates that when the amount of silane coupling agent is insufficient, the interfacial bridging between the resin and inorganic fillers (carbon black, magnetic iron oxide) cannot be fully achieved, leading to decreased compatibility; when the amount is too high, excessive coupling agent easily agglomerates, damaging the stability of the toner system.

[0267] Comparative Example 10: γ-aminopropyltriethoxysilane (not a vinyl-based coupling agent of this application) was used instead of vinyltriethoxysilane, and the remaining conditions were the same as in Example 1. Table 1 shows that Comparative Example 10 had an agglomeration rate of 8.9% (exceeding the acceptable threshold), a charge change rate of 17.4% (exceeding the acceptable threshold), a melting point range of 22°C, 6 spots per page, and an image density attenuation rate of 5.3%. These results indicate that vinyl-based silane coupling agents can copolymerize with the double bonds of modified styrene-acrylic resin to form a stable "organic-inorganic bridging structure"; while amino-based coupling agents lack copolymerization ability and have insufficient interfacial bonding, resulting in a significant decrease in the toner's anti-agglomeration properties and charge stability.

[0268] Comparative Example 11 showed an agglomeration rate of 9.8% (exceeding the acceptable standard), a charge change rate of 18.6% (not meeting requirements), a melting point range of 21℃, 6 spots per page, and an image density attenuation rate of 5.9%. This demonstrates that the low surface energy of polyethylene wax can significantly reduce the friction coefficient between toner particles and has a synergistic effect with tricyclohexyl citrate to regulate melting behavior; while petroleum wax lacks sufficient lubrication and synergistic effect, making it difficult to suppress particle adhesion and uneven melting, ultimately leading to toner performance degradation.

[0269] Comparative Example 12 used dicyclohexyl phthalate (not tricyclohexyl citrate) as a plasticizer. The plasticizer addition amounts in Comparative Examples 13 and 14 were 0.4 parts (below the optimal range) and 12 parts (above the optimal range), respectively, all deviating from the requirements of the present invention. Other conditions were the same as in Example 1. Table 1 shows that: Comparative Example 12 had an agglomeration rate of 7.5%, a charge change rate of 13.8% (unacceptable), and a melting point range of 18°C; Comparative Example 13 had an agglomeration rate of 8.3%, a charge change rate of 15.1% (unacceptable), and a melting point range of 16°C; Comparative Example 14 had an agglomeration rate of 10.8% and a charge change rate of 19.3% (unacceptable). This indicates that tricyclohexyl citrate can regulate melting characteristics by embedding into the resin molecular chain, and within an addition range of 2-4 parts, it can balance melt flowability and material rigidity; while other types of plasticizers or amounts outside this range will lead to increased particle adhesion or a narrowing of the melting point range, compromising the stability of the toner system.

[0270] The above embodiments are preferred implementations of this application. In addition, this application can be implemented in other ways. Any obvious substitutions without departing from the concept of this application are within the protection scope of this application.

Claims

1. A high-stability toner, characterized by, Components including the following mass parts: Modified styrene-acrylic resin 60~70 parts, carbon black 10~12 parts, charge regulator 5~6 parts, silane coupling agent 5~6 parts, magnetic iron oxide 18~22 parts, lubricant 2~4 parts, plasticizer 2~4 parts; The modified styrene-acrylic resin includes the following raw materials: Hard monomer, soft monomer, functional monomer, initiator, emulsifier, dispersant, and the mass ratio of hard monomer, soft monomer, functional monomer, initiator, emulsifier, and dispersant is (71~81):(18~22):(3~5):(0.6~1.0):(1.6~2.4):(180~220); The preparation process of the modified styrene-acrylic resin includes: mixing hard monomer, soft monomer, functional monomer, emulsifier, and dispersant to prepare pre-emulsion; seed emulsion polymerization is carried out on part of the pre-emulsion and part of the initiator, then the remaining pre-emulsion and the remaining initiator are added, and polymerization reaction is carried out; after the reaction is completed, the pH is adjusted to 6.5~7.0, and after drying and crushing, the modified styrene-acrylic resin is obtained; The plasticizer is tri-cyclohexyl citrate; The silane coupling agent includes at least one of vinyl triethoxysilane and vinyl trimethoxysilane.

2. The carbon powder according to claim 1, characterized in that, The particle size Dv90 of the carbon black is 5μm~10μm.

3. The carbon powder according to claim 1, characterized in that, The charge regulator is a quaternary ammonium salt charge regulator.

4. The carbon powder according to claim 1, characterized in that, The particle size Dv90 of the magnetic iron oxide is 5μm~10μm.

5. The carbon powder of claim 1, wherein, The lubricant is polyethylene wax.

6. The carbon powder of claim 1, wherein, The hard monomer includes styrene, methyl methacrylate, and isobornyl methacrylate; The soft monomer is butyl acrylate; The functional monomer includes acrylic acid and glycidyl methacrylate; The initiator is potassium persulfate; The emulsifier includes polyoxyethylene octyl phenol ether and sodium dodecyl sulfate; The dispersant is water.

7. The carbon powder according to claim 6, characterized in that, The modified styrene-acrylic resin includes the following components by mass: Styrene 43~48 parts, methyl methacrylate 19~22 parts, isobornyl methacrylate 9~11 parts, butyl acrylate 18~22 parts; acrylic acid 2~3 parts, glycidyl methacrylate 1~2 parts, potassium persulfate 0.6~1.0 parts, polyoxyethylene octyl phenol ether 1.0~1.4 parts, sodium dodecyl sulfate 0.6~1.0 parts, and water 180~220 parts.

8. The carbon powder of claim 1, wherein, The specific process of the seed emulsion polymerization of part of the pre-emulsion and part of the initiator is: 1 / 4 of the pre-emulsion is taken, 1 / 2 of the potassium persulfate solution is added dropwise at 75℃, and after the dropwise addition is completed, it is kept at 75℃ for 30min~60min; And / or, the specific process of the polymerization reaction after the remaining pre-emulsion and the remaining initiator are added is: the remaining pre-emulsion and the remaining initiator are added dropwise into the seed emulsion polymerization completed liquid, after the dropwise addition is completed, it is heated to 85℃, and reacted at 85℃ for 60min~90min.

9. A method for producing the carbon powder according to any one of claims 1 to 8, characterized by, Including the following steps: The modified styrene-acrylic resin, carbon black, charge regulator, silane coupling agent, magnetic iron oxide, lubricant, and plasticizer are mixed by mass parts, and carbon powder is prepared by melt extrusion, crushing, and grading.

10. Use of a carbon powder in xerography or laser printing, characterized in that, The carbon powder includes the carbon powder according to any one of claims 1 to 8 or the carbon powder prepared by the preparation method according to claim 9. The carbon powder includes the carbon powder according to any one of claims 1 to 8 or the carbon powder prepared by the preparation method according to claim 9.

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