Positively-charged non-magnetic toner and preparation method thereof
By using a composition of hydrophobic silica with a specific particle size and a hexagonal boron nitride micropowder as an anti-bonding aid in a positively charged non-magnetic toner, the problem of the toner being agglomerated in a high temperature and high humidity environment is solved, and its stability and printing quality are improved.
Patent Information
- Application Number
- CN202510328125.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-10-25
- Filing Date
- 2025-03-19
- Publication Date
- 2025-06-13
AI Technical Summary
The existing positive-electric non-magnetic toners are prone to clumping in high temperature and high humidity environments, affecting the clarity and color density of printing.
A composition including a binder resin, a non-magnetic colorant, a positive charge control agent, a release agent and a hydrophobic silica and hexagonal boron nitride micropowder of a specific particle size is used as a positive non-magnetic toner of the anti-bonding aid. By wrapping the anti-bonding aid on the outer surface of the toner masterbatch, the stability of the toner is improved and its sensitivity to a high temperature and high humidity environment is reduced.
It effectively improves the stability of the positive-electric non-magnetic toner, reduces its agglomeration risk in high-temperature and high-humidity environments, thereby improving the quality and stability of printing.
Smart Images
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Abstract
Description
Technical Field
[0001] The present application relates to the field of printing consumables, and particularly to a positively charged non-magnetic toner and a preparation method thereof. Background Art
[0002] A positively charged non-magnetic toner refers to toner powder that is positively charged and uses a non-magnetic colorant as the colorant. Among them, the positively charged non-magnetic toner should have appropriate triboelectric charging properties, charging stability, appropriate fluidity, and good fixing performance, which is beneficial to output images with stable colors and quality.
[0003] Currently, the positively charged non-magnetic toner in related technologies is relatively sensitive to environmental conditions. For example, in a high-temperature environment, the binder resin or release agent in the toner changes, resulting in toner caking, which easily affects the uniformity of the distribution of the positively charged non-magnetic toner on the printing drum or paper, thereby affecting the print clarity and color density. Another example is that in a high-humidity environment, the number of water molecules in the air increases, and more water is adsorbed on the surface of the positively charged non-magnetic toner, resulting in caking of the positively charged non-magnetic toner, which also affects the image clarity and color density of the positively charged non-magnetic toner during printing. Summary of the Invention
[0004] In order to improve the problem that the positively charged non-magnetic toner in related technologies is greatly affected by environmental temperature and humidity and is prone to caking, the present application provides a positively charged non-magnetic toner and a preparation method thereof.
[0005] In a first aspect, a positively charged non-magnetic toner provided by the present application adopts the following technical solution: A positively charged non-magnetic toner includes 100 parts by weight of binder resin, 10.8 - 15.6 parts by weight of non-magnetic colorant, 4.5 - 5.5 parts by weight of positive charge control agent, 1 - 5 parts by weight of release agent, and 8 - 10 parts by weight of anti-caking aid. Among them, the anti-caking aid includes hydrophobic silica with a particle size range of 40 - 50 nm and hexagonal boron nitride micropowder with a particle size range of 100 - 200 nm, and the weight ratio of the hydrophobic silica to the hexagonal boron nitride micropowder is (10 - 15):1.
[0006] In addition to the basic binder resin, non-magnetic colorant, positive charge control agent, and release agent, the positively charged non-magnetic toner of the present application also adds a composition of hydrophobic silica and hexagonal boron nitride micropowder with specific particle sizes as an anti-caking aid to prevent the positively charged non-magnetic toner from caking. These anti-caking aids are wrapped on the outer surface of the positively charged non-magnetic toner masterbatch, which is beneficial to improving the stability of the positively charged non-magnetic toner and reducing the influence of the high-temperature and high-humidity environment on the positively charged non-magnetic toner. However, it should be noted that the incorporation amount of the hexagonal boron nitride micropowder should not be too high, otherwise it will affect the melt fluidity of the positively charged non-magnetic toner and is not conducive to improving the printing quality and printing stability.
[0007] In some specific embodiments, the adhesive resin is a composition of a styrene-acrylonitrile copolymer and a styrene-2-ethylhexyl acrylate copolymer, and the weight ratio of the styrene-acrylonitrile copolymer to the styrene-2-ethylhexyl acrylate copolymer is (3.5-4.5):1; wherein, the glass transition temperature of the styrene-acrylonitrile copolymer is 100-120 °C; in the styrene-2-ethylhexyl acrylate copolymer, the weight ratio of the two monomers, styrene and 2-ethylhexyl acrylate, is (75-85):(15-25).
[0008] In this application, the positive non-magnetic toner uses a composition of a styrene-acrylonitrile copolymer and a styrene-2-ethylhexyl acrylate copolymer as the adhesive resin, and controls the glass transition temperature of the styrene-acrylonitrile copolymer to be 100-120 °C. In the styrene-2-ethylhexyl acrylate copolymer, the weight ratio of the two monomers, styrene and 2-ethylhexyl acrylate, is (75-85):(15-25), which is beneficial to reducing the fixing temperature of the positive non-magnetic toner. At the same time, it can further improve the melt fluidity of the positive non-magnetic toner and reduce the adhesion of the positive non-magnetic toner on the fixing roller.
[0009] In some specific embodiments, the styrene-2-ethylhexyl acrylate copolymer is obtained by reacting the two monomers, styrene and 2-ethylhexyl acrylate, under the initiation of a peroxide initiator in an environment of 78-88 °C for 3-4 h.
[0010] In some specific embodiments, in the styrene-2-ethylhexyl acrylate copolymer, the weight ratio of the two monomers, styrene and 2-ethylhexyl acrylate, is (80-85):(15-20).
[0011] In some specific embodiments, the non-magnetic colorant uses at least one of carbon black, cyan black, monoazo black dye, bisazo black dye, and trisazo black dye.
[0012] Carbon black, cyan black, monoazo black dye, bisazo black dye, trisazo black dye, etc. have the advantage of good thermal stability, which is beneficial to improving the color stability of the positive non-magnetic toner.
[0013] In some specific embodiments, the positive charge control agent uses a styrene-alkyl methacrylate-methacrylic acid quaternary ammonium salt monomer copolymer, and in the styrene-alkyl methacrylate-methacrylic acid quaternary ammonium salt monomer copolymer, the weight ratio of the three monomers, styrene, alkyl methacrylate, and methacrylic acid quaternary ammonium salt monomer, is (60-70):(10-15):(20-25).
[0014] In this application, the positive charge control agent is preferably a styrene-alkyl methacrylate-quaternary ammonium methacrylate monomer copolymer. Among them, the positive charge control agent has good compatibility with the binder resin, which is conducive to the uniform dispersion of the positive charge control agent.
[0015] In some specific embodiments, the styrene-alkyl methacrylate-quaternary ammonium methacrylate monomer copolymer is obtained by reacting three monomers, namely styrene, alkyl methacrylate, and quaternary ammonium methacrylate monomer, under the initiation of a peroxide initiator in an environment of 82-90 °C for 3-3.5 hours.
[0016] In some specific embodiments, the quaternary ammonium methacrylate monomer is methylacryloyloxyethyltrimethylammonium chloride.
[0017] In this application, the positive charge control agent is further preferably a styrene-alkyl methacrylate-methylacryloyloxyethyltrimethylammonium chloride copolymer, which can further reduce the minimum fusing temperature and adhesion of the positively charged non-magnetic toner, and is conducive to improving the printing quality and stability of the positively charged non-magnetic toner.
[0018] In some specific embodiments, the release agent is at least one of paraffin wax, polypropylene wax, and polyethylene wax.
[0019] The addition of wax, polypropylene wax, and polyethylene wax can improve the anti-offset property of the positively charged non-magnetic toner and is conducive to reducing the adhesion of the positively charged non-magnetic toner to the fusing roller.
[0020] Second, a preparation method of a positively charged non-magnetic toner provided by this application adopts the following technical solution: A preparation method of a positively charged non-magnetic toner includes the following steps: S1. Uniformly mix the binder resin, non-magnetic colorant, positive charge control agent, and release agent, melt them evenly, then extrude, cool, and pulverize to obtain a toner masterbatch; S2. Add an anti-blocking aid to the toner masterbatch and mix evenly to obtain the toner.
[0021] This application prepares the positively charged non-magnetic toner by the above method, which is conducive to obtaining a toner with little influence from high-temperature and high-humidity environments and good stability.
[0022] In some specific embodiments, in step S1, the melting temperature is 130-140 °C.
[0023] In this application, controlling the melting temperature at 130-140 °C is conducive to promoting the uniform mixing of each raw material.
[0024] In some specific embodiments, the particle size range of the toner masterbatch is 10 - 20 μm.
[0025] In this application, controlling the particle size range of the toner masterbatch to be 10 - 20 μm is beneficial to the melt flow of the positively charged non-magnetic toner on the one hand, and on the other hand, is beneficial to the uniform and stable adhesion of the anti-sticking aid on the outer peripheral side of the toner masterbatch.
[0026] In summary, this application includes at least the following beneficial technical effects: (1) In addition to the basic binder resin, non-magnetic colorant, positive charge control agent, and release agent, the positively charged non-magnetic toner of this application also adds a composition of hydrophobic silica and hexagonal boron nitride micropowder with a specific particle size as an anti-sticking aid to prevent the positively charged non-magnetic toner from sticking. These anti-sticking aids are wrapped on the outer surface of the positively charged non-magnetic toner masterbatch, which is beneficial to improving the stability of the positively charged non-magnetic toner and reducing the influence of the high-temperature and high-humidity environment on the positively charged non-magnetic toner. However, it should be noted that the incorporation amount of hexagonal boron nitride micropowder should not be too high, otherwise it will affect the melt fluidity of the positively charged non-magnetic toner and is not conducive to improving the printing quality and printing stability.
[0027] (2) In this application, the positively charged non-magnetic toner uses a composition of styrene-acrylonitrile copolymer and styrene-2-ethylhexyl acrylate copolymer as the binder resin, and controls the glass transition temperature of the styrene-acrylonitrile copolymer to be 100 - 120 °C. In the styrene-2-ethylhexyl acrylate copolymer, the weight ratio of the two monomers of styrene and 2-ethylhexyl acrylate is (75 - 85):(15 - 25), which is beneficial to reducing the fixing temperature of the positively charged non-magnetic toner. At the same time, it can further improve the melt fluidity of the positively charged non-magnetic toner and reduce the adhesion of the positively charged non-magnetic toner on the fixing roller.
[0028] (3) In this application, the positive charge control agent is further preferably a copolymer of styrene-alkyl methacrylate-methacryloyloxyethyl trimethyl ammonium chloride, which can further reduce the minimum fixing temperature and adhesion of the positively charged non-magnetic toner, and is beneficial to improving the printing quality and stability of the positively charged non-magnetic toner. Specific Embodiments
[0029] The following is further described in combination with specific experiments. Examples
[0030]
Example 1
[0031] In this embodiment, the adhesive resin is a composition of styrene-acrylonitrile copolymer and styrene-2-ethylhexyl acrylate copolymer with a weight ratio of 7:1. Among them, the glass transition temperature of the styrene-acrylonitrile copolymer is 105-110 °C. The styrene-2-ethylhexyl acrylate copolymer is obtained by reacting 75 kg of styrene and 25 kg of 2-ethylhexyl acrylate monomers under the initiation of 1.2 kg of benzoyl peroxide at 78 °C for 4 h.
[0032] The non-magnetic colorant specifically uses carbon black.
[0033] The positive charge control agent specifically uses a copolymer of styrene-dimethylaminoethyl acrylate trimethyl ammonium chloride. Among them, the copolymer of styrene-dimethylaminoethyl acrylate trimethyl ammonium chloride is obtained by reacting 75 kg of styrene and 25 kg of dimethylaminoethyl acrylate trimethyl ammonium chloride under the initiation of 1.0 kg of benzoyl peroxide at 82 °C for 3.5 h.
[0034] The release agent specifically uses polyethylene wax.
[0035] The anti-blocking aid specifically uses hydrophobic silica with a particle size range of 40-50 nm and hexagonal boron nitride micropowder with a particle size range of 100-200 nm. Among them, the weight ratio of hydrophobic silica to hexagonal boron nitride micropowder is 10:1. In this embodiment, the hydrophobic silica is produced by the vapor phase method.
[0036] In this embodiment, the preparation method of the positive charge non-magnetic toner includes the following steps: S1. After uniformly mixing the adhesive resin, non-magnetic colorant, positive charge control agent, and release agent, melt them uniformly at 130 °C, then extrude, cool, and pulverize to obtain a toner masterbatch with a particle size range of 10-20 μm. S2. Add the anti-blocking aid to the toner masterbatch and mix it evenly at a stirring speed of 800 r / min to obtain the toner.
[0037]
Example 2
[0038] In this embodiment, the adhesive resin is a composition of styrene-acrylonitrile copolymer and styrene-2-ethylhexyl acrylate copolymer with a weight ratio of 7:1. Among them, the glass transition temperature of the styrene-acrylonitrile copolymer is 110-120 °C. The styrene-2-ethylhexyl acrylate copolymer is obtained by reacting 85 kg of styrene and 20 kg of 2-ethylhexyl acrylate monomers under the initiation of 1.2 kg of benzoyl peroxide at 88 °C for 3 h.
[0039] The non-magnetic colorant is specifically cyanine black.
[0040] The positive charge control agent is specifically a copolymer of styrene-dimethylaminoethyl acrylate trimethylammonium chloride. Among them, the copolymer of styrene-dimethylaminoethyl acrylate trimethylammonium chloride is obtained by reacting 80 kg of styrene with 20 kg of dimethylaminoethyl acrylate trimethylammonium chloride under the initiation of 1.5 kg of benzoyl peroxide at 90 °C for 3 h.
[0041] The release agent is specifically polypropylene wax.
[0042] The anti-blocking aid is specifically hydrophobic silica with a particle size range of 40 - 50 nm and hexagonal boron nitride micropowder with a particle size range of 100 - 200 nm. Among them, the weight ratio of hydrophobic silica to hexagonal boron nitride micropowder is 15:1. In this embodiment, the hydrophobic silica is produced by the vapor phase method.
[0043] In this embodiment, the preparation method of the positive charge non-magnetic toner includes the following steps: S1. After uniformly mixing the binder resin, non-magnetic colorant, positive charge control agent, and release agent, melt them uniformly at 140 °C, then extrude, cool, and pulverize to obtain toner masterbatch with a particle size range of 10 - 20 μm; S2. Add the anti-blocking aid to the toner masterbatch, and mix them uniformly at a stirring speed of 850 r / min to obtain the toner.
[0044]
Example 3
Example 1
[0045]
Example 4
Example 1
[0046]
Example 5
Example 4
[0047]
Example 6
Example 4
[0048]
Example 7
Example 4
[0049]
Example 8
Example 7
[0050] Comparative Example
Comparative Example 1
Example 1
[0051]
Comparative Example 2
Example 1
[0052]
Comparative Example 3
[0053] [Comparative Example 4] A positively charged non-magnetic toner, which is different from [Example 1] in that: no anti-blocking aid is added.
[0054] Performance detection test 1. Thermal stability: The positively charged non-magnetic toners prepared in each example and comparative example were put into an environment with a constant temperature of 80 °C, left standing for 72 h, and then cooled. The sieve residue rates of the positively charged non-magnetic toners in each example and comparative example when passing through a 200-mesh sieve before and after heating were respectively tested, and the difference between the sieve residue rate of the positively charged non-magnetic toner passed through a 200-mesh sieve after heating and the sieve residue rate of the positively charged non-magnetic toner passed through a 200-mesh sieve before heating was recorded. The larger the difference value a, the larger the caking proportion of the positively charged non-magnetic toner, and the worse the thermal stability. Among them, in this application, the difference value a less than 2% is qualified.
[0055] 2. Moisture stability: The positively charged non-magnetic toners prepared in each example and comparative example were put into an environment with a constant temperature of 25 °C and a humidity of 90%, and left standing for 168 h. The sieve residue rates of the positively charged non-magnetic toners in each example and comparative example when passing through a 200-mesh sieve before and after the moisture resistance test were respectively tested, and the difference between the sieve residue rate of the positively charged non-magnetic toner passed through a 200-mesh sieve after the moisture resistance test and the sieve residue rate of the positively charged non-magnetic toner passed through a 200-mesh sieve before the moisture resistance test was recorded. The larger the difference value b, the larger the caking proportion of the positively charged non-magnetic toner, and the worse the moisture stability. Among them, in this application, the difference value b less than 2% is qualified.
[0056] 3. Evaluation of printing image effect: The positively charged non-magnetic toners prepared in each example and comparative example were added to the toner cartridge of the printer, and the temperature of the fixing roller was raised from 140 °C to 180 °C for a fixing test. During the fixing test, if the fixing effect was unqualified, the temperature was raised by 10 °C and then the fixing was carried out again. After the fixing was qualified, the lowest temperature corresponding to the qualified fixing was recorded.
[0057] 4. Print image stability: The positively charged non-magnetic toner prepared from each example and the comparative example was added to the toner cartridge of the printer. In an environment with a temperature of 25°C and a humidity of 75%, the temperature of the fusing roller was controlled at 180°C, and 2000 images with a printing rate of 5% were continuously printed. The color density value and the background ash value of the 1st and 10000th images were compared. Among them, the higher the color density value, the clearer and more detailed the printed image; the lower the background ash value, the cleaner the background and the smaller the occurrence of unnecessary gray or dirt. In this application, a color density value above 1.35 and a background ash value below 2 are considered qualified. In addition, after printing, the amount of the positively charged non-magnetic toner adhered to the fusing roller was measured.
[0058] Table 1 Table 2 Combining Example 1 and Comparative Examples 1-4 and combining the test results in Tables 1-2, it can be seen that: Hydrophobic silica and hexagonal boron nitride micropowders with different particle sizes are compounded in a specific ratio as anti-bonding additives, which can effectively improve the stability of the positively charged non-magnetic toner under high temperature and high humidity conditions, and is beneficial to improving printing stability. In addition, when hydrophobic silica is coated on the outer surface of the toner masterbatch alone, it is easy to cause an increase in the fusing temperature of the positively charged non-magnetic color masterbatch. Matching a certain proportion of hexagonal boron nitride micropowders with better thermal conductivity is beneficial to reducing the fusing temperature of the positively charged non-magnetic color masterbatch.
[0059] Combining Example 1 and Examples 3-4 and combining the test results in Tables 1-2, it can be seen that: In the binder, when the weight ratio of styrene-acrylonitrile copolymer to styrene-2-ethylhexyl acrylate copolymer is in the range of (3.5-4.5):1, it is beneficial to improve the lowest fusing temperature of the positively charged non-magnetic toner, reduce the adhesion of the positively charged non-magnetic toner on the fusing roller, and improve the background ash value during the printing of the positively charged non-magnetic toner.
[0060] Combining Examples 4-8 and combining the test results in Tables 1-2, it can be seen that: The positive charge control agent is preferably a styrene-alkyl methacrylate-methacrylic acid quaternary ammonium salt monomer copolymer prepared from three monomers of styrene, alkyl methacrylate, and methacrylic acid quaternary ammonium salt in a weight ratio of (60-70):(10-15):(20-25). It can not only obtain the lowest fusing temperature before the positively charged non-magnetic toner is coated and modified, but also further reduce the adhesion of the positively charged non-magnetic toner, which is beneficial to improving the printing stability of the positively charged non-magnetic toner.
[0061] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art may make modifications to this specific embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.
Claims
1. A positive non-magnetic toner, characterized in that: The invention comprises 100 parts by weight of a binder resin, 10.8-15.6 parts by weight of a non-magnetic colorant, 4.5-5.5 parts by weight of a positive charge control agent, 1-5 parts by weight of a release agent and 8-10 parts by weight of an anti-adhesive agent, wherein the anti-adhesive agent comprises hydrophobic silica with a particle size range of 40-50 nm and hexagonal boron nitride powder with a particle size range of 100-200 nm, and the weight ratio of the hydrophobic silica to the hexagonal boron nitride powder is (10-15):
1.
2. A positive non-magnetic toner according to claim 1, characterized in that: The adhesive resin is a composition of styrene-acrylonitrile copolymer and styrene-2-ethylhexyl acrylate copolymer, wherein the weight ratio of the styrene-acrylonitrile copolymer to the styrene-2-ethylhexyl acrylate copolymer is (3.5-4.5):1; wherein the glass transition temperature of the styrene-acrylonitrile copolymer is 100-120°C; and in the styrene-2-ethylhexyl acrylate copolymer, the weight ratio of styrene and 2-ethylhexyl acrylate monomers is (75-85):(15-25).
3. A positive non-magnetic toner according to claim 2, characterized in that: In the styrene-2-ethylhexyl acrylate copolymer, the weight ratio of styrene and 2-ethylhexyl acrylate is (80-85): (15-20).
4. A positive non-magnetic toner according to any one of claims 2 to 3, characterized in that: The positive charge control agent is a styrene-alkyl methacrylate-quaternary ammonium methacrylate monomer copolymer, in which the weight ratio of styrene, alkyl methacrylate and quaternary ammonium methacrylate monomer is (60-70): (10-15): (20-25).
5. A positive non-magnetic toner according to claim 4, characterized in that: The methacrylic acid quaternary ammonium salt monomer is methacryloyloxyethyl trimethyl ammonium chloride.
6. A positive non-magnetic toner according to any one of claims 1 to 3, characterized in that: The non-magnetic colorant is at least one of carbon black, cyanine black, monoazo black dye, disazo black dye and trisazo black dye.
7. A positive non-magnetic toner according to any one of claims 1 to 3, characterized in that: The release agent is at least one of paraffin wax, polypropylene wax and polyethylene wax.
8. A method for preparing a positive non-magnetic toner according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, uniformly mixing a binder resin, a non-magnetic colorant, a positive charge control agent and a release agent, melting them uniformly, and then extruding, cooling and pulverizing them to obtain a toner masterbatch; S2. Add an anti-adhesive additive to the toner masterbatch and mix them evenly to obtain a toner.
9. The method for preparing a positive non-magnetic toner according to claim 8, characterized in that: In step S1, the melting temperature is 130-140°C.
10. The method for preparing a positive non-magnetic toner according to claim 8, characterized in that: The particle size of the toner masterbatch is in the range of 10-20 μm.