JP3439598B2 - Carrier for electrostatic latent image development - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to electrophotography, electrostatic recording,
For dry two-component developer used for recording, electrostatic printing, etc.
About the rear. [0002] 2. Description of the Related Art Dry developing method used for electrophotography
Powder toner rubbed against the triboelectric charging member
A visible image is formed by electrostatically adhering to a latent image.
You. [0003] In this dry development method, only toner is mainly used.
So-called one-component development method and glass beads,
Magnetic material carriers or their surfaces made of resin
Using a mixture of coated carrier and toner,
There is a so-called two-component system. [0004] The two-component developer used in the latter is relatively
Fine toner particles on both surfaces of large carrier particles
Is held by the electric force generated by the friction of
When approached, the electric field formed by the electrostatic latent image
Toner particles overcome the binding force with the carrier particles
Is developed on the electrostatic latent image. And development
Agent repeats while replenishing toner consumed by development
used. [0005] Accordingly, the carrier particles can be used during prolonged use.
Always have the desired polarity of toner particles and sufficient charge amount
Must be triboelectrically charged. However, between particles
Impact, particle and mechanical agitation in the developing device, or
With the heat generated by them, the toner fuses to the carrier particle surface,
So-called spent toner is generated and the charge characteristics of carrier particles are
Performance decreases with use time. Along with that, the background of the image
Replace the entire developer due to contamination and toner scattering
Need to be obtained. To prevent such spent, key
On the surface of the carrier core material, a resin with low surface energy, for example,
By coating with fluorine resin, silicone resin, etc.
The life of carriers has been extended. Carry coated with low surface energy resin
The following are examples of a. JP
55-127569: Room temperature curing type silicone resin and positive belt
Carrier coated with conductive nitrogen resin. JP-A-55-157
751: Contains at least one modified silicone resin
Carrier coated with coating material. JP-A-56-14035
8: Room temperature curing type silicone resin and styrene acrylic
Carrier having a resin coating layer containing a resin. JP
57-96355: Silicone having two or more layers of core particle surfaces
Carry coated with resin to prevent adhesion between layers
A. JP-A-57-96356: Silicone on core particle surface
Carrier coated with multiple layers of resin. JP-A-58-20705
4: Surface coated with silicone resin containing silicon carbide
Career. JP-A-61-110161: 20 dyn
Positively charged with a material showing a critical surface tension of less than / cm
Sex carrier. JP-A-62-273576: Fluoroalkyl
Carrier coated with coating material containing ruacrylate
And a toner comprising a chromium-containing azo dye. However, in recent years, to improve image quality,
Toner tends to be smaller and toner
Pents are becoming more common. Also, full color
In order to obtain a sufficient color tone, use a resin with a low softening point.
Since it is necessary to use it, it is
The amount of spent on the carrier increases, and the toner charge
Of toner, toner scattering and background stains occur. Full color
-In an electrophotographic system, when the charge amount decreases,
The image density in the illuminated area is easily changed, and high image quality can be maintained.
There is no present. [0009] SUMMARY OF THE INVENTION The object of the present invention is to
Less spent on the carrier,
No degradation, toner scattering, and background stains occur, and
Stable image quality even for full-color toner with low softening point
For dry two-component development with high durability that can maintain image quality
To provide a career. [0010] Means for Solving the Problems: Using a developer for a long time
And a slight amount of spent, especially with color toner.
Even if this occurs, the carrier is coated because the softening point of the resin is low.
And the charging area decreases (the amount of toner charge)
Drop). Therefore, the inventors of the present invention have proposed repetition of the carrier.
Utilizes scraping of carrier film during use, resulting in triboelectric charging
With the appearance of a high-performance carrier coat layer,
Suppress deterioration of carrier charging ability caused by spent
This led to the present invention. That is, the present invention providesas followsIt is. [0013]Dry two-component having a resin coating layer on the core material surface
In the developer carrier, the thickness direction of the resin coating layer
In contrast, the closer to the core material, the higher the triboelectric charging capacity of the coating layer
And the coating layer contains at least a silicone resin.
And that the firing temperature differs in the thickness direction.
Characteristic carrier for developing electrostatic latent images. Here, when the carrier is repeatedly used, the key is
In order to remove the carrier film little by little,
Molecular weight, molecular weight distribution, composition and resin of small molecular weight
By containingIt is possible,Silicone resin
Has low surface energy and the film
Therefore, it is optimal for the above purpose. [0015] [0016] [0017] [0018] [0019] [0020] [0021] [0022] [0023] Silicon used as coating resin of the present invention
Known resins can be used as the resin. example
For example, silicone containing a repeating unit represented by the following general formula
Resin. [0025] Embedded image (Wherein R is a hydrogen atom, a halogen atom, a hydride
Roxy group, methoxy group or C₁~ C_FourLower alkyl group
Alternatively, it represents a phenyl group. ) Straight silicone tree
As fats, KR271, KR272, KR282, K
R252, KR255, KR152 (Shin-Etsu Chemical Co., Ltd.)
), SR24OO, SR2406 (Toray Dow Corning)
G silicone). Also, modified silicone
Examples include epoxy-modified silicone and acrylic-modified silicone.
Corn, phenol-modified silicone, urethane-modified silicone
Corn, polyester modified silicone, alkyd modified
And silicone. As an example of modified silicone
Epoxy modified: ES-100IN) acrylic modified
Silicone: KR-5208, Polyester modified: KR
-5203, alkyd denaturation: KR-206, urethane
Denaturation: KR-305 (made by Shin-Etsu Chemical Co., Ltd.), Epo
Xy modification: SR2115, alkyd modification: SR211
0 (manufactured by Dow Corning Toray Silicone Co., Ltd.). In the present invention, as the coating resin,Also
TheCan be used in combination with the above silicone resin
Noh. For example, polystyrene, chloropolystyrene
, Poly-α-methylstyrene, styrene-chlorostyrene
Styrene copolymer, styrene-propylene copolymer, styrene
-Butadiene copolymer, styrene-vinyl chloride copolymer
Body, styrene-vinyl acetate copolymer, styrene-male
Acid copolymer, styrene-acrylate copolymer
(Styrene-methyl acrylate copolymer, styrene-A
Ethyl acrylate copolymer, styrene-butyl acrylate
Copolymer, styrene-octyl acrylate copolymer,
Tylene-phenyl acrylate copolymer), styrene-
Methacrylic acid ester copolymer (styrene-methacrylic
Methyl acrylate copolymer, styrene-ethyl methacrylate copolymer
Coal, styrene-butyl methacrylate copolymer, styrene
Styrene-α-phenyl methacrylate copolymer)
Methyl chloroacrylate copolymer, styrene-acryloyl
Styrene such as nitrile-acrylate copolymer
Resin, epoxy resin, polyester resin, polyethylene
Resin, polypropylene resin, ionomer resin, poly
Urethane resin, ketone resin, ethylene-ethyl acryle
Plate, xylene resin, polyamide resin, pheno
Resin, polycarbonate resin, melamine resin, etc.
No. Heating the silicone resin in the thickness direction
To change the charging ability by changing the temperature
The heating temperature should be increased each time one layer is applied while applying multiple layers.
It is possible by changing (lowering the temperature). or,
From the side closer to the core material toward the surface,
Composition, amount of aminosilane coupling agent, amino group
The number, amino series and ratio of resistance modifier
Creates two types of coating solutions and applies one of them
However, if the other coating solution is added at an arbitrary ratio,
good. Aminosilane coupling that can be used in the present invention
For example, the following chemical formulas are used for the coloring agent. Primary amine [0031] Embedded image Primary + secondary amine [0033] Embedded imageSecondary amine [0035] Embedded image Tertiary amine [0037] Embedded image Quaternary amine [0039] Embedded image [0040] Embedded imageThe present inventors have developed an aminosilane coupling agent.
After examining the characteristics when using
It was found to have characteristics. That is, (1) amino
The larger the amount of the run babbling agent, the higher the charging ability,
(2) The aminosilane coupling agent has a large number of amino groups
The higher the charging ability. Also, (3) large amino series
Aminosilane coupling agent has higher charging ability
No. Further, when the resistance of the coating material is reduced, the frictional charging
The ability can be reduced. Thickness resistance
Materials that can be adjusted include conductive ZnO, A
Metal powder such as l, SnO made by various methods_Twoand,
SnO doped with various elements_Two, Boride such as T
iB_Two, ZnB_Two, MoB_Two, Silicon carbide, and conductive
Polymers (polyacetylene, polyparaphenylene, poly
(Para-phenylene sulfide), polypyrrole, poly
Examples include ethylene and carbon black. [0043] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described with reference to Production Examples, Examples,
This will be described using a comparative example. In the following example, "part"
Represents parts by weight. [0044] Production Example 1: Preparation of Toner A     100 parts of polyester (weight average molecular weight 12000)     Copper phthalocyanine pigment 2 parts     Polarity control agent (the following structural formula) 2 parts [0045] Embedded image The above materials are kneaded at 120 ° C. with a hot roll.
Then, after cooling and solidifying, pulverize and classify, volume average particle size
A full-color cyan toner of 7.1 μm was obtained. Further, with respect to 100 parts of the toner,
0.5 parts of R972 (manufactured by Nippon Aerosil Co., Ltd.)
Thus, a toner A was obtained. [0048] Production Example 2: Preparation of Toner B     100 parts of polyester (weight average molecular weight 12000)     5 parts of carbon black     Chromium-containing azo dye (the following structural formula) 2 parts [0049] Embedded imageThe above material is kneaded at 120 ° C. with a hot roll.
Then, after cooling and solidifying, pulverize and classify, volume average particle size
7.3 μm full color black toner was obtained. Further, with respect to 100 parts of the toner,
0.5 parts of R972 (manufactured by Nippon Aerosil Co., Ltd.)
Thus, a toner B was obtained. [0052] Production Example 3: Preparation of carrier C     Silicone resin U (weight average molecular weight about 4000)                         1000g toluene solution with 10% solids [0053] Embedded image [0054]     Catalyst V (CH_Three)_TwoSn (OCOCH_Three)_Two                  5g The above dispersion is converted to a ferrite core material having a volume average particle size of 50 μm.
(Saturation magnetic moment at 1K Gauss = 65 emu /
g) For 5 kg, using a fluidized bed type coating apparatus
Under an atmosphere of 100 ° C. at a rate of about 50 g / min.
Apply over 20 minutes and then apply this silicone resin
The ferrite particles thus obtained are heated at 200 ° C. for one hour,
Carrier C was obtained. [0055] Production Example 4: Preparation of carrier D     Coating liquid (1): same silicone resin U as used in Production Example 3                                                               500g                     2.5 g of the same catalyst V used in Production Example 3     Coating liquid (2): same silicone resin U as used in Production Example 3                                                               500g                     2.5 g of the same catalyst V used in Production Example 3                     Silica R972 (Nippon Aerosil Co., Ltd.) 5g 5 kg ferrite core same as Production Example 3 is coated
The liquid (1) was applied at a rate of 50 g per minute. Same as start of application
Sometimes dispersion liquid (2) is coated at a rate of 25 g / min.
(1), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating of coating liquid immediately before completion of coating
When the ratio of the liquid (2) was measured, it was about 60%. After the coating is completed, the silicone resin is further
Heat the applied ferrite particles at 200 ° C for 1 hour
Thus, a carrier D was obtained. [0058] Production Example 5: Preparation of carrier E     Epoxy-modified silicone (SR2115 / 50% solids, Toray Dowcor                                 200g     800 g of toluene The above coating solution was applied to the same ferrite core material as in Production Example 3.
Then, using a fluidized bed type coating apparatus,
In an atmosphere, apply at a rate of about 50 g / min for 20 minutes.
Cloth, and further coated with this silicone resin
The particles are heated at 200 ° C. for 1 hour to obtain carrier E
Was. [0059] Production Example 6: Preparation of carrier F     Coating liquid (1): Silicone resin U 500g                     2.5g of catalyst V     Coating liquid (3): Epoxy-modified silicone (SR2115 / solid content 50% Manufactured by Toray Dow Corning Silicone Co., Ltd.) 100g                     400 g of toluene 5 kg ferrite core same as Production Example 3 is coated
Liquid (3) was applied at a rate of 50 g per minute. Same as start of application
Sometimes the dispersion liquid (1) is coated at a rate of 25 g / min.
(3), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. SR2 for the coating solution immediately before the end of coating
When the ratio of 115 (coating liquid (3)) was measured, it was found to be about 40%.
%Met. After the application is completed, further apply this silicone resin
Heat the applied ferrite particles at 200 ° C for 1 hour
Thus, a carrier F was obtained. Production Example 7: Preparation of carrier G In the same manner as in Production Example 3, a silicone resin was coated.
Heated ferrite particles at 280 ° C for 1 hour
A G was obtained. Production Example 8: Preparation of carrier H The coating liquid was prepared in exactly the same manner as in Production Example 3 and was about 50 g.
/ Min for 12 minutes (about 600g)
Take out ferrite particles and heat at 280 ° C for 1 hour
And then apply for 2 minutes (about 100g)
Heat for 1 hour, then 240 ° C, 22
Heat in the order of 0 ° C and 200 ° C for 1 hour each,
Rear H was obtained. [0063] Production Example 9: Preparation of carrier I     Silicone resin U 1000g     5g of catalyst V     Aminosilane coupling agent W NH_Two(CH_Two)_ThreeSi (OCH_Three)_Three                                                                   5g After thoroughly stirring the above coating solution with a homomixer,
Under the same conditions as in Example 3, the surface of the ferrite particles
Coated with resin and heated at 200 ° C for 1 hour to carry
A was obtained. [0064] Production Example 10: Preparation of carrier J     Coating liquid (1): Silicone resin U 500g                     2.5g of catalyst V     Coating liquid (4): Silicone resin U 500g                     2.5g of catalyst V                     Aminosilane coupling agent W                     NH_Two(CH_Two)_ThreeSi (OCH_Three)_Three           2.5g 5 kg ferrite core same as Production Example 3
Liquid (4) was applied at a rate of 50 g per minute. Same as start of application
Sometimes the dispersion liquid (1) is coated at a rate of 25 g / min.
(4), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating with coating liquid immediately before completion of coating
When the ratio of the liquid (4) was measured, it was about 40%. After the coating is completed, the silicone resin is further
Heat the applied ferrite particles at 200 ° C for 1 hour
Thus, a carrier J was obtained. [0067] Production Example 11: Preparation of carrier K     Silicone resin U 1000g     5g of catalyst V     Aminosilane coupling agent X 5g     NH_Two(CH_Two)_TwoNH (CH_Two)_TwoNH (CH_Two)_ThreeSi (OCH_Three)_Three After thoroughly stirring the above coating solution with a homomixer,
Under the same conditions as in Example 3, the surface of the ferrite particles
Coated with resin and heated at 200 ° C for 1 hour to carry
I got AK. [0068] Production Example 12: Preparation of carrier L     Coating liquid (5): 500 g of silicone resin U                     2.5g of catalyst V                     2.5 g of aminosilane coupling agent W                             NH_Two(CH_Two)_ThreeSi (OCH_Three)_Three     Coating liquid (6): 500 g of silicone resin U                     2.5g of catalyst V                     2.5 g of aminosilane coupling agent X            NH_Two(CH_Two)_TwoNH (CH_Two)_TwoNH (CH_Two)_ThreeSi (OCH_Three)_Three 5 kg ferrite core same as Production Example 3 is coated
Liquid (6) was applied at a rate of 50 g per minute. Same as start of application
Sometimes, the dispersion liquid (5) is coated at a rate of 25 g / min.
(6), at 100 ° C while dispersing uniformly
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating with coating liquid immediately before completion of coating
When the ratio of the liquid (6) was measured, it was about 40%. After the coating is completed, the silicone resin is further
Heat the applied ferrite particles at 200 ° C for 1 hour
Thus, a carrier L was obtained. [0071] Production Example 13: Preparation of carrier M     Silicone resin U 1000g     5g of catalyst V     Aminosilane coupling agent Y (quaternary amine) 5g [0072] Embedded image The above coating solution was sufficiently stirred with a homomixer.
After stirring, ferrite particles were obtained under the same conditions as in Production Example 3.
Coat the surface with silicone resin and apply at 200 ° C for 1 hour.
The carrier M was obtained by heating. [0074] Production Example 14: Preparation of carrier N     Coating liquid (7): 500 g of silicone resin U                     2.5g of catalyst V                     2.5 g of aminosilane coupling agent Z (tertiary amine) [0075] Embedded image [0076]   Coating liquid (8): Silicone resin U 500g                   2.5g of catalyst V                   2.5 g of aminosilane coupling agent Y (quaternary amine) 5 kg ferrite core same as Production Example 3 is coated
Liquid (8) was applied at a rate of 50 g per minute. Same as start of application
Sometimes the dispersion liquid (7) is coated at a rate of 25 g / min.
(8), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating with the coating liquid immediately before the end of coating
When the ratio of the liquid (8) was measured, it was about 40%. After the coating is completed, the silicone resin is further
Heat the applied ferrite particles at 200 ° C for 1 hour
Thus, a carrier N was obtained. [0079] Production Example 15: Preparation of carrier O     Silicone resin U 500g     2.5g of catalyst V     SnO_Two                                                     20g The above coating solution was applied to the same ferrite core material as in Production Example 3.
Then, using a fluidized bed type coating apparatus,
In an atmosphere, apply at a rate of about 50 g / min for 20 minutes.
Cloth and ferrite coated with this silicone resin
The particles are heated at 200 ° C. for 1 hour to obtain carrier O
Was. [0080] Production Example 16: Preparation of carrier P     Coating liquid (9): 500 g of silicone resin U                     2.5g of catalyst V                     SnO_Two                                     10g     Coating liquid (1): Silicone resin U 500g                     2.5g of catalyst V 5 kg ferrite core same as Production Example 3 is coated
The liquid (1) was applied at a rate of 50 g per minute. Same as start of application
Occasionally, the dispersion liquid (9) is coated at a rate of 25 g / min.
(1), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating with coating liquid immediately before completion of coating
When the ratio of the liquid (9) was measured, it was about 60%. After the coating is completed, the silicone resin is further
Heat the applied ferrite particles at 200 ° C for 1 hour
Thus, a carrier P was obtained. [0083] Production Example 17: Preparation of carrier Q     Silicone resin U 500g     2.5g of catalyst V     Carbon # 3600B (Mitsubishi Kasei) 4g The above coating solution was applied to the same ferrite core material as in Production Example 3.
Then, using a fluidized bed type coating apparatus,
In an atmosphere, apply at a rate of about 50 g / min for 20 minutes.
Cloth and ferrite coated with this silicone resin
The particles are heated at 200 ° C. for 1 hour to obtain Carrier Q
Was. [0084] Production Example 18: Preparation of carrier R     Coating liquid (10): Silicone resin U 500g                       2.5g of catalyst V                       Carbon # 3600B (Mitsubishi Kasei) 2g     Coating liquid (1): Silicone resin U 500g                     2.5g of catalyst V 5 kg ferrite core same as Production Example 3 is coated
The liquid (1) was applied at a rate of 50 g per minute. Same as start of application
Sometimes, the dispersion liquid (10) is coated at a rate of 25 g / min.
(1), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating with coating liquid immediately before completion of coating
When the ratio of the liquid (10) was measured, it was about 60%. Paint
After the cloth is finished,
The particles are heated at 200 ° C. for 1 hour,
Obtained. [0086] Production Example 19: Preparation of carrier S     Coating liquid (11): Silicone resin U5OOg                       2.5g of catalyst V                       Carbon # 3600B (Mitsubishi Kasei) 2g     Coating liquid (12): 500 g of silicone resin U                       2.5g of catalyst V                       Aminosilane coupling agent Y (quaternary amine)                                                               2.5g 5 kg ferrite core same as Production Example 3 is coated
The liquid (12) was applied at a rate of 50 g per minute. Start of application
At the same time, the dispersion liquid (11) was coated at a rate of 25 g / min.
(1), 100 ° C atmosphere while uniformly dispersing
Apply at a rate of about 50 g / min over 20 minutes
Was. Coating with coating liquid immediately before completion of coating
When the ratio of the liquid (11) was measured, the coating liquid was about 60%.
(12) was about 40%. After the coating is completed, the silicone resin is further
Heat the applied ferrite particles at 200 ° C for 1 hour
Therefore, the closer to the core material of the coating layer, the lower the carbon content
Carrier S containing a large amount of aminosilane coupling agent
Obtained. [0089]Reference Example 1 Carrier D (100 parts) and toner A (6 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge was −18.7 μC / g. Next, the Pretail 500 (Ricoh full product)
Color copier) to output images in single color mode
At the same time, high image quality without background contamination was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
06 μm, and the toner charge amount is −16.4 μC /
g. Comparative Example 1 Toner A (6 parts) for carrier C (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge was -20.3 μC / g. Next, Britail 500 (Ricoh full product)
Color copier) to output images in single color mode
At the same time, high image quality without background contamination was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
The toner scattered from about 20,000 sheets, and at 30,000 sheets
, The background stain became remarkable. After the continuous copy test, the carrier coating was reduced to 0.
08m and the toner charge amount is -13.2μC / g
And had been low. [0097]Reference example 2 Carrier F (100 parts) and toner A (6 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At that time, the toner charge was -22.8 μC / g. On the other hand, a carrier having the same thickness as the carrier F
For E, a developer was prepared in the same manner as above,
27.2 μC / g.
The charge amount was high. Therefore, when the film thickness is the same, the surface has
High content of oxy-modified silicone SR2115
The higher the charge amount of the toner is. Next, the developer prepared with the carrier F was used.
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
06 μm and the toner charge amount is -20.9 μC /
g. [0103]Example 1 Toner H (5 parts) for carrier H (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge amount was -21.7 μC / g. On the other hand, a carrier having substantially the same thickness as the carrier H
For the rear G, a developer was prepared in the same manner as described above.
Where, −29.5 μC / g, compared to carrier H,
The toner charge was high. Therefore, when the film thickness is the same, the silicone resin
If the heating temperature for the toner is increased, the toner B
In this case, the toner charge amount is high. Next, a developer prepared with the carrier H was used.
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
09 μm and the toner charge amount was -20.1 μC /
g. Comparative Example 2 Toner C (5 parts) for carrier C (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge was −19.2 μC / g. Next, the Pretail 500 (Ricoh full product)
Color copier) to output images in single color mode
At the same time, high image quality without background contamination was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
The toner scattered from about 20,000 sheets, and at 30,000 sheets
, The background stain became remarkable. After the continuous copy test, the carrier coating was reduced to 0.
09m and the toner charge is -12.9μC / g
And had been low. [0113]Reference Example 3 Toner J (6 parts) for carrier J (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge amount was −23.0 μC / g. On the other hand, a carrier having the same thickness as the carrier J
For I, the developer was prepared in the same manner as above.
And −26.8 μC / g, which is lower than that of the carrier J.
The toner charge was high. Therefore, when the film thickness is the same, the surface
The higher the content ratio of the minosilane coupling agent, the
-The charge amount is high. Next, the developer prepared with the carrier H was used.
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
08 μm, and the toner charge amount is −19.5 μC /
g. [0119]Reference example 4 Toner L (6 parts) for carrier L (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge amount was −25.1 μC / g. On the other hand, a carrier having the same thickness as the carrier L
For K, the developer was prepared in the same manner as above.
And −28.9 μC / g.
The toner charge was high. Therefore, when the film thickness is the same,
Ratio of aminosilane coupling agent with a large number of amino groups
Is higher, the charge amount is higher. Next, the developer prepared with the carrier H was used.
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coat was reduced to 0.
06 μm, and the toner charge amount is −22.3 μC /
g. [0125]Reference Example 5 Toner A (6 parts) for carrier N (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At that time, the charge amount of the toner was −26.0 μC / g. On the other hand, a carrier having the same thickness as the carrier N
For M, a developer was prepared in the same manner as above.
-32.3 μC / g, which is smaller than that of the carrier N.
The toner charge was high. Therefore, when the film thickness is the same,
Ratio of aminosilane coupling agent with high amino group series
When the rate is high, the charge amount is high. Next, the developer prepared with the carrier H was used.
, Pretail 500 (Ricoh full color copier)
When the image was displayed in the single color mode of
High image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
07 μm, and the toner charge amount was −24.0 μC /
g. [0131]Reference example 6 Toner P (6 parts) for carrier P (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge was −18.1 μC / g. On the other hand, a carrier having the same thickness as the carrier P
For O, a developer was prepared in the same manner as above.
And -16.3 μC / g.
The toner charge was low. Therefore, when the film thickness is the same, the surface is low.
When the resistance material is small, the charge amount is high. Next, using the developer prepared with the carrier P,
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
07 μm, and the toner charge amount is −16.5 μC /
g. [0137]Reference Example 7 Toner R (5 parts) for carrier R (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At this point, the toner charge was −17.9 μC / g. On the other hand, a carrier having the same thickness as the carrier R
Regarding Q, the developer was prepared in the same manner as above.
-14.5 μC / g, compared to the carrier R,
The toner charge was low. Therefore, when the film thickness is the same, the surface is low.
If the amount of carbon, which is a resistance substance, is small, the charge amount will increase.
ing. Next, the developer prepared with the carrier R was used.
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 30,000 sheets was performed.
High image quality without stain on the background even after 30,000 copies
Was. After the continuous copy test, the carrier coating was reduced to 0.
06 μm and the toner charge amount is −18.2 μC /
g. [0143]Reference Example 8 Toner S (5 parts) for carrier S (100 parts)
In addition, the mixture was stirred with a ball mill for 10 minutes to prepare a developer.
At that time, the toner charge was -24.0 μC / g. Next, the developer prepared with the carrier R was used.
, Pretail 500 (Ricoh full color copier)
Where the image was displayed in the monochrome mode of
Image quality was obtained. Subsequently, a continuous copy test of 50,000 sheets was performed.
However, even after 50,000 sheets, high image quality is maintained without stain on the background.
Was. After the continuous copy test, the carrier coating was reduced to 0.
11 μm, and the toner charge amount was −23.8 μC /
g and hardly changed. The above evaluations are summarized in Table 1. [0148] [Table 1] [0149] As described above, the resin layer of the carrier core material is
The material closer to the core material with a material having a high triboelectric charging ability.
The frictional charging ability is low even when used for a long time.
Carrier that does not fall down and has no background
Thus, high image quality is maintained.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Akemi Sugiyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A 7-160059 (JP, A) JP-A-5-204189 (JP, A) JP-A-5-134467 (JP, A) JP-A-57-96355 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9 / Ten

Claims (1)

(57) [Claims 1] A dry type 2 component having a resin coating layer on the surface of a core material.
In the carrier for developer, the thickness of the resin coating layer
In contrast, the closer to the core material, the higher the triboelectric charging capacity of the coating layer
And the coating layer contains at least a silicone resin.
And that the firing temperature differs in the thickness direction.
Characteristic carrier for developing electrostatic latent images.