CN105005184B - Carrier for electrostatic image developer and two-component developer containing the same - Google Patents
Carrier for electrostatic image developer and two-component developer containing the same Download PDFInfo
- Publication number
- CN105005184B CN105005184B CN201510422164.8A CN201510422164A CN105005184B CN 105005184 B CN105005184 B CN 105005184B CN 201510422164 A CN201510422164 A CN 201510422164A CN 105005184 B CN105005184 B CN 105005184B
- Authority
- CN
- China
- Prior art keywords
- carrier
- developer
- coating layer
- silica particles
- electrostatic image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Developing Agents For Electrophotography (AREA)
Abstract
The invention discloses a carrier for an electrostatic image developer and a two-component developer, and solves the problem that the conventional carrier is easy to lose efficacy under an extremely high-temperature and high-humidity environment, and even causes the developer to be caked. The carrier comprises a carrier core material and a coating layer coated on the carrier core material, and the resin coating layer comprises large-particle-size silica particles. The two-component developer contains the carrier for electrostatic image developer and a toner. The carrier has excellent performance of resisting extreme high temperature and high humidity, and the developer containing the carrier can still maintain good developing performance and does not agglomerate after long-term operation in the environment. The two-component developer has excellent developing performance and good durability, is more favorable for avoiding the damage to hardware caused by the caking of the developer in the printing process under the high-temperature and high-humidity environment, and can keep good developing performance.
Description
Technical Field
The present invention relates to a carrier for developing electrostatic images and a two-component developer for developing electrostatic images containing the same.
Background
With the rapid development of full-color printing and high-speed printing and the increasing requirements of people on image fineness and image reliability, the application of the two-component developer is more and more extensive. As one of the important components in the two-component developer, the carrier, has the double functions of transporting the carbon powder and enabling the carbon powder to be triboelectrically charged, and plays an important role in the whole developing process.
The developing device is often applied to some extreme environments, especially high-temperature and high-humidity environments, so that the requirement on the weather resistance of the developer is very high, and under the high-temperature and high-humidity environments, the developing device has the characteristic that the internal temperature of the developing device is often higher than room temperature due to heat release of a fixer and heat release of internal stirring friction, and carbon powder has the characteristics of low glass transition temperature and low melting point, so that the carbon powder is easily melted and attached to the surface of a carrier under the severe environment, the carrier can be failed, and even the developer can be agglomerated under severe conditions, so that a developing assembly is damaged.
In order to solve this problem, patent CN101211129A proposes to add titanium oxide particles containing anatase type crystals and rutile type crystals to the coating layer, but since the hardness of the metal oxide particles is high, the external addition on the carbon powder surface is likely to be detached by long-term abrasion, which causes contamination of the carrier surface, and the use cost thereof is relatively high. Although many developers have done much work to improve the charging stability of the developer in the extreme high temperature and high humidity environment, few reports have been made to solve the problem that the developer is likely to be caked in the extreme environment. In addition, due to the low Tg characteristic of the chemical carbon powder, under an extremely high-temperature high-humidity environment, even if the temperature is increased by 1-2 ℃, the developer can be caused to agglomerate, the high-temperature high-humidity test condition before the carrier manufacturer leaves the factory is generally 30 ℃ and 80 percent at present, the actual use environment is more common than 30 ℃, and how to maintain the use performance of the developer at higher temperature is not researched similarly before.
Disclosure of Invention
The invention aims to solve the technical problems and provide a carrier for an electrostatic image developer, which can prevent carbon powder from being thermally melted and attached to the surface of the carrier to cause the failure of the carrier and even cause the caking of the developer when the carrier is serious under an extremely high-temperature and high-humidity environment (more than or equal to 30 ℃ and 80 percent of humidity).
The present invention also provides a two-component developer for developing electrostatic images, comprising the above carrier and toner.
The carrier for the electrostatic image developer comprises a carrier core material and a resin coating layer coated on the carrier core material, wherein the resin coating layer comprises silica particles with large particle size. The inventor researches and discovers that when the dispersion liquid of the coating layer is prepared, silica particles with large particle size are added and then the coating is carried out on the carrier, the silica can form slight bulges on the surface of the coating layer, and the slight bulges can effectively prevent the carbon powder from being attached to the surface of the carrier after being melted by heat, thereby effectively preventing the carrier from losing efficacy and more serious developer agglomeration caused by the heat melting of the carbon powder on the surface of the carrier under the high-temperature and high-humidity environment. The large-particle size silica particles preferably have a particle size of 0.1 μm to 0.3. mu.m, and if the particle size is less than 0.1. mu.m, no effective protrusions are formed on the surface of the carrier, and thus, the hot-melt adhesion of the carbon powder to the surface of the carrier cannot be effectively prevented, whereas if the particle size is more than 0.3. mu.m, the surface of the carrier is excessively rough, thereby affecting the fluidity of the carrier.
The invention provides a carrier for electrostatic image developer, wherein the content of silicon dioxide particles in a resin coating layer accounts for 0.5-2% of the total mass of the coating layer, if the content is less than 0.5%, bulges with sufficient area can not be formed on the surface of the carrier, thereby affecting the using effect, and if the content is more than 2%, the surface of the carrier is too rough, thereby affecting the fluidity of the carrier.
The silica particles are preferably hydrophobic silica. In order to avoid that the carrier electrification amount is influenced by the water absorption of the silica particles under the high-temperature and high-humidity environment, hydrophobic silica is preferably used.
Further, the silica particles are preferably positively charged silica particles to prepare a carrier suitable for matching electronegative carbon powders, so that the carrier is positively charged, and in order not to affect the charge amount of the carrier, the positively charged silica particles are preferably used.
If the coating layer weight is 1 to 3% based on 100% by weight of the carrier core material, and less than 1%, it is difficult to obtain sufficient durability and appropriate resistance of the carrier, and if it is more than 3%, the carrier resistance is high.
The carrier for electrostatic image developer of the present invention is preferably controlled to have a volume resistivity of 109-1015Omega cm. If the volume resistivity of the carrier is less than 109Ω · cm, when the toner concentration in the developer is lowered due to repeated use, charge may be injected into the carrier so that the carrier itself may be developed, and when the volume resistivity of the carrier is more than 1015Ω · cm may have an adverse effect on the picture such as significant edge effect or false contour.
The present invention provides a carrier for electrostatic image developer, which has a volume average particle diameter D50 of 20 μm to 60 μm. When the particle diameter of the carrier is too large, the collision energy in the developing device is also increased, so that the carrier is likely to be broken or broken, and the charging surface area of the toner is decreased, so that the charging function of the toner is lowered, and the reproducibility of details of the developed image is lowered, and a clear image cannot be formed. When the particle diameter of the carrier is too small, uniformity of carrier particles is lowered and magnetic force of individual carriers is also lowered, so that carrier attachment and mutual adhesion between carrier particles may occur.
Furthermore, the carrier containing large-particle-size silica particles in the resin coating layer can also contain other functional particles, such as methyl methacrylate particles, melamine particles and the like, besides the carbon nanotube particles. The added particles are more beneficial to the carrier to still have good charging performance after long-term use, so that the carrier is ensured to have good durability.
In order to ensure high durability and good environmental stability of a carrier, it is necessary to coat the surface of a carrier core material with a resin layer, and the main purposes thereof are: preventing the carbon powder component from polluting (consuming) the surface of the carrier; the fluctuation of the charge amount under the conditions of high temperature, high humidity, low temperature and low humidity is avoided, and the high-definition image quality under different environments is ensured; adjusting the resistance of the developer; the charge amount and charge amount distribution were controlled.
The material of the resin coating layer is mainly various polymer resins, and preferably, the resin of the coating layer contains at least one of acrylic resin, fluorine resin, and silicone resin. The carrier containing acrylic resin coating has good durability because the resin layer is not easy to fall off, and the fluorine resin and the silicon resin have lower surface energy, so that the pollution of carbon powder to the surface of the carrier is reduced when the carrier coated by the resin and the carbon powder are rubbed, and the service life of the carrier is prolonged.
In order to improve the electrical resistance and the charging performance of the carrier, various functional particles, such as conductive particles for adjusting the electrical resistance, e.g., carbon black, titanium dioxide, tin dioxide, and aluminum trioxide, and particles for improving the charging performance, e.g., melamine and acrylic resin, may be added to the coating layer, and the addition amount of the functional particles may be appropriately selected according to the actual needs. Because the thickness of the carrier coating layer is very thin, generally between 0.05 and 1 μm, the particle size of the additive particles is generally required to be dispersed to the nanometer level by using a dispersing device so as to ensure the performance of the additive particles.
The coating apparatus for the carrier is mainly a fluidized bed, a kneader, a high-speed mixer, etc., and the coating method can be selected from a dry coating method and a wet coating method depending on whether or not a solvent is used, and is not described in detail.
Has the advantages that:
the large-particle-size hydrophobic positive charged silica particles are introduced into the coating layer of the carrier, so that an effective convex shape can be formed on the surface of the coating layer of the carrier, the surface energy of the resin of the coating layer can be effectively reduced, the developer can be effectively prevented from losing efficacy due to the fact that carbon powder is attached to the surface of the carrier through hot melting and even from caking possibly caused in severe cases when the carbon powder is used in a high-temperature high-humidity environment, and the developer has high image fineness and high reliability under the high-temperature high-humidity environment.
Detailed Description
Example 1
Preparation of carrier core material:
dispersing 720g of iron oxide, 230g of manganese oxide and 50g of magnesium oxide in 1000g of water, adding 5g of polyacrylic acid dispersing agent, grinding the mixture to about 1 micron of average particle size by using a sand mill, adding 15g of polyvinyl alcohol as a binder, and obtaining 10-80 micron of granulation powder by using spray granulation equipment. Putting the granulated powder into an electric furnace, presintering at 850 ℃, adding a sintering furnace into 1000g of water after sintering, adding 5g of polyacrylic acid dispersing agent, grinding the mixture to about 1 micron of average particle size by using a sand mill again, adding 15g of polyvinyl alcohol as a binder, and obtaining 10-80 micron of granulated powder by using spray granulation equipment. The granulated material was charged into an electric furnace and subjected to secondary sintering at 1240 ℃. And crushing, grading and screening the sintering material to obtain a carrier core material of 36 micrometers.
Preparation of resin dispersion:
40g of a polymethyl methacrylate-styrene resin (MMA/St. 4/1) was dissolved in 360g of toluene, and 4g of carbon black and 0.4g of hydrophobic and positively charged silica particles having a large particle diameter (particle diameter of 0.1 μm) were added thereto, and the mixture was ground at room temperature for 10min using a sand mill to obtain a resin dispersion containing carbon black and silica particles having an average particle diameter of 300nm or less. In the following examples, unless otherwise specified, all the silica particles used were hydrophobic and positively charged silica particles.
Coating of the carrier:
2KG of carrier core material was placed in a 2L kneader, stirring was started, a resin dispersion containing carbon black and silica particles was slowly poured in, the temperature was raised to 70 ℃ and after stirring for half an hour, the toluene solvent was removed by evacuation. The carrier was poured out, sieved using a 200-mesh sieve to remove large particles, and then classified using an air classifier to remove small particles, to obtain a carrier.
Example 2
The conditions were the same as in example 1 except that 0.2g of silica particles were used.
Example 3
The conditions were the same as in example 1 except that 0.6g of silica particles were used.
Example 4
The conditions were the same as in example 1 except that 0.8g of silica particles were used.
Example 5
The same procedure as in example 1 was repeated except that silica particles having a particle size of 0.2 μm were used.
Example 6
The same procedure as in example 1 was repeated except that silica particles having a particle size of 0.3 μm were used.
Comparative example 1
The conditions were the same as in example 1 except that no silica particles were used.
Comparative example 2
The conditions were the same as in example 1 except that 0.1g of silica particles were used.
Determination of volume resistivity
The test method is referred to standard JB/T9437-1999, and the test results are shown in Table two.
The volume average particle diameter was measured using a laser diffraction particle size distribution analyzer model LS-230 manufactured by Beckmann Coulter Ltd., U.S.A., and the density and bottom ash of a print sheet were measured using X-Rite 938 (manufactured by X-Rite integration).
Printing agglomeration experiment:
10 parts of carbon powder and 90 parts of the above-mentioned carriers of examples 1 to 6 and comparative examples 1 to 2 were mixed and stirred to obtain developers of examples 1 to 6 and comparative examples 1 to 2, and standard test sheets were output on a printer. The test method comprises the following steps: the test is started after the laboratory is stable for more than 12 hours in a high-temperature and high-humidity environment.
Firstly, printing evaluation test is carried out in a high-temperature high-humidity (30 ℃, 80%) environment laboratory, 10000 test pages are printed, and the condition of developer caking is observed; and then, increasing the temperature (32 ℃ and 80%) of a high-temperature high-humidity environment laboratory, printing 10000 test pages, and observing the caking condition of the developer again, wherein the results show that all developers in the embodiment are not caked under two environments, and the carbon powder hardly causes pollution to the surface of the carrier through the analysis of a scanning electron microscope and the change of the charge amount before and after printing, while the caking phenomenon of the developer is generated in the comparative example 1 under two environments, while the caking phenomenon of the developer is not generated in the comparative example 2 under 30 ℃ and 80%, but the remarkable caking phenomenon of the developer is generated at 32 ℃ and 80%, and partial carbon powder is thermally melted and attached to the surface of the carrier under 30 ℃ and 80% through the observation of the scanning electron microscope, so that partial carrier is invalid.
Table 130 ℃, charge amount tested in 80% environment, density and bottom ash data of printed swatches, and blocking experimental data:
from the above data, it can be seen that the initial charge amount and the printing condition were good regardless of the addition of silica particles, but after 10000 sheets were printed, the charge amount was significantly decreased and the density was also significantly decreased and the bottom ash was significantly increased without adding silica in an amount of 0.5 wt% or less, indicating that silica can not only effectively prevent the developer from blocking under an extremely high temperature and high humidity environment, but also has a positive effect on maintaining the stability of the printed sheet image under a high temperature and high humidity environment.
TABLE 2 volume resistivity and volume average particle size data for examples and comparative examples
| Carrier | Volume resistivity (omega cm) | Volume average particle diameter (μm) |
| Example 1 | 3.2×1013 | 36.79 |
| Example 2 | 4.5×1013 | 36.38 |
| Example 3 | 2.8×1013 | 37.37 |
| Example 4 | 2.3×1013 | 37.05 |
| Example 5 | 3.7×1013 | 36.59 |
| Example 6 | 4.8×1013 | 37.17 |
| Comparative example 1 | 5.1×1013 | 37.26 |
| Comparative example 2 | 2.9×1013 | 37.75 |
Claims (6)
1. A carrier for electrostatic image developer comprises a carrier core material and a resin coating layer thereof, and is characterized in that silica particles with the particle size of 0.2-0.3 μm are added in the resin coating layer, the silica particles are hydrophobic silica particles, and the content of the silica particles in the resin coating layer accounts for 0.5-2 wt% of the total mass of the coating layer;
the resin coating layer accounts for 1-3% of the total weight of the carrier core material;
the volume resistivity of the carrier is 109-1015Omega cm, volume average particle diameter D50 of 20-60 μm.
2. The carrier for electrostatic image developer according to claim 1, wherein the silica particles are positively charged silica particles.
3. The electrostatic charge image developing carrier according to claim 1, wherein the resin coating layer contains at least one of an acrylic resin, a fluorine-based resin, and a silicone resin.
4. The electrostatic image developer carrier according to claim 1, wherein the resin coating layer further contains resistance adjusting agent particles dispersed in a nanometer order.
5. The carrier for electrostatic image developer according to claim 4, wherein the resistance adjusting agent is carbon black.
6. A two-component developer comprising the carrier for electrostatic image developer according to any one of claims 1 to 5 and a toner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510422164.8A CN105005184B (en) | 2015-07-17 | 2015-07-17 | Carrier for electrostatic image developer and two-component developer containing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510422164.8A CN105005184B (en) | 2015-07-17 | 2015-07-17 | Carrier for electrostatic image developer and two-component developer containing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105005184A CN105005184A (en) | 2015-10-28 |
| CN105005184B true CN105005184B (en) | 2020-07-07 |
Family
ID=54377903
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510422164.8A Active CN105005184B (en) | 2015-07-17 | 2015-07-17 | Carrier for electrostatic image developer and two-component developer containing the same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105005184B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105372958A (en) * | 2015-12-09 | 2016-03-02 | 湖北鼎龙化学股份有限公司 | Resin-coated carrier and preparation method therefor, and bi-component developing agent |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59232362A (en) * | 1983-06-15 | 1984-12-27 | Ricoh Co Ltd | Carrier for electrostatic latent image developer |
| CN1920676A (en) * | 2005-08-23 | 2007-02-28 | 富士施乐株式会社 | Electrostatic latent image developer and image-forming apparatus |
| JP2007279657A (en) * | 2005-08-25 | 2007-10-25 | Ricoh Co Ltd | Carrier and developer, and image forming method, image forming apparatus, and process cartridge |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1657595B1 (en) * | 2004-11-11 | 2013-05-15 | Powdertech Co., Ltd. | Resin-coated ferrite carrier for electrophotographic developer, its production method, and electrophotographic developer using the resin-coated ferrite carrier |
| JP4625417B2 (en) * | 2005-04-06 | 2011-02-02 | 株式会社リコー | Carrier and two-component developer |
| JP2008170814A (en) * | 2007-01-12 | 2008-07-24 | Sharp Corp | Developer |
-
2015
- 2015-07-17 CN CN201510422164.8A patent/CN105005184B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59232362A (en) * | 1983-06-15 | 1984-12-27 | Ricoh Co Ltd | Carrier for electrostatic latent image developer |
| CN1920676A (en) * | 2005-08-23 | 2007-02-28 | 富士施乐株式会社 | Electrostatic latent image developer and image-forming apparatus |
| JP2007279657A (en) * | 2005-08-25 | 2007-10-25 | Ricoh Co Ltd | Carrier and developer, and image forming method, image forming apparatus, and process cartridge |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105005184A (en) | 2015-10-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4996126A (en) | Developer having specific spheriodicity | |
| KR20120076057A (en) | Toner for developing electrostatic image and method, apparatus for forming image and method for forming image using the same | |
| JP6022459B2 (en) | Charge control agent composition for external addition and electrostatic image developing toner | |
| US20170212439A1 (en) | Toner formulations having improved toner usage efficiency | |
| JP6769233B2 (en) | Carrier for electrostatic latent image developer, developer, and image forming device | |
| CN101876795B (en) | Resin-coated carrier, method of manufacturing the same, two-component developer including resin-coated carrier, developing device and image forming apparatus | |
| JP2006038961A (en) | Electrostatic charge image developing carrier, electrostatic charge image developer, method for manufacturing electrostatic charge image developing carrier, and image forming apparatus | |
| KR100938180B1 (en) | Toner with excellent image uniformity | |
| US4230787A (en) | Magnetic toner for developing latent electrostatic images and a process for the preparation thereof | |
| JP2009181005A (en) | Electrostatic latent image development toner | |
| JP5153486B2 (en) | toner | |
| EP2808738B1 (en) | Magnetic carrier, two-component developer, developer for replenishment, and image forming method | |
| CN105005184B (en) | Carrier for electrostatic image developer and two-component developer containing the same | |
| JP3332727B2 (en) | Image forming method and toner | |
| EP3686677A1 (en) | Carrier core material for electrophotographic developer and method for producing the same, and carrier for electrophotographic developer and developer containing said carrier core material | |
| JPH01191155A (en) | Carrier for dry process developer | |
| US7393622B2 (en) | Two-component developing agent for electrophotography | |
| JPS6228772A (en) | Dry developing agent | |
| CN105652616B (en) | Carrier core material for two-component electrostatic image developer and carrier | |
| JP2008268562A (en) | Pulverized toner and manufacturing method therefor | |
| JP3168366B2 (en) | Two-component developer | |
| CN103869645A (en) | Carrier core material and preparation method thereof as well as carrier of electrostatic image developing agent | |
| JP2019120797A (en) | Electrophotographic carrier and electrostatic latent image developer | |
| JPH11327195A (en) | Electrostatic image developing toner | |
| JP5089479B2 (en) | Developing apparatus and developing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: 430057 Hubei city of Wuhan Province Economic and Technological Development Zone East Jinghe Road No. 1 Applicant after: HUBEI DINGLONG Co.,Ltd. Address before: 430057 Hubei city of Wuhan Province Economic and Technological Development Zone East Jinghe Road No. 1 Applicant before: Hubei Dinglong Chemical Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |