JPH01237561A - Developer for developing electrostatic latent image - Google Patents

Abstract

PURPOSE:To obtain an always stable image by adding fine silica powder of 0.1-5mu average size having an amino group on the surface to a negative chargeable toner. CONSTITUTION:The fine silica powder of 0.1-5mu average size having the amino group on the surface is added to the negative chargeable toner. Namely, the fine silica powder of 0.1-5mu grain size which has the amino group on the surface and is treated by amino silane and/or amino-modified silicone oil is added and mixed to and with the negative chargeable toner powder prepd. by dispersing and incorporating a magnetic material, charge control agent, coloring agent, offset preventive agent, other additives, etc., at need into a binder resin. Since the negative chargeability of the toner is relieved, the charge-up phenomenon is suppressed. The stable image is thus obtd. even after long-term use.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc., and in particular uses triboelectric charging. The present invention relates to a developer comprising an insulating component toner which is developed as an insulating component.

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 2,297°89
Specification No. 1, Japanese Patent Publication No. 42-23910 (U.S. Patent No. 3,688,383), Japanese Patent Publication No. 43-247
Publication No. 48 (U.S. Patent No. 4,071,381)
Many methods are known, such as, but in general, an electrical latent image is formed on a photoreceptor by various means using a photoconductive substance, and then the latent image is transferred to developer powder (hereinafter referred to as toner). ), and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure, solvent vapor, etc. to obtain a copy. Furthermore, when a process for transferring a toner image is included, a process for removing residual toner on the photoreceptor is usually provided.

Development methods for visualizing electrical latent images using toner include, for example, the magnetic brush method described in U.S. Pat. No. 2,874,063, and the magnetic brush method described in U.S. Pat. There are methods that use two-component developers such as cascade development, but two-component development is relatively stable and produces good images, but on the other hand, it causes deterioration of the carrier and the mixing ratio of toner and carrier. It has the disadvantage that it fluctuates. In order to avoid the drawbacks of the above-mentioned two-component development method, an in-place method using an insulating magnetic or non-magnetic one-component toner is known. For development using such insulating component toner, a thin layer of toner is formed on a developing sleeve, which is a developer carrier, using a magnetic blade or a pressing member whose tip is pressed against the developing sleeve. Generally, the toner on the developing sleeve is subjected to development by applying a necessary charge by friction to the toner on the developing sleeve.

Such a one-component development method has excellent properties such as no fluctuation in toner density and the ability to make the device compact and inexpensive, but in order to form a visible image of good quality,
It is necessary for the toner to have high fluidity and to be uniformly charged, and for this purpose, fine silica powder has conventionally been added and mixed to toner powder.

Such fine silica powder has traditionally been made hydrophobic in order to increase charging stability in various temperature environments, and negatively charged toner has been added with negatively charged silica fine powder. ing.

However, when fine silica powder with strong negative charging property is used, frictional charging between the toner and the sleeve occurs repeatedly in areas where toner is not consumed, such as solid white areas, resulting in the toner becoming too charged. A phenomenon occurs in which a charge-up phenomenon occurs and the image density decreases.

Such a phenomenon is noticeable in a developing system using a pressing member in which the toner is strongly rubbed on the sleeve.

This phenomenon can be resolved by scraping off the toner that has adhered to the sleeve with a scraper, etc., and replacing the toner on the sleeve. If the coating or scraper precision is not improved, problems such as poor scraping may occur, which is difficult in practice.

As a result of various studies, the present inventors have found that the above-mentioned drawbacks can be overcome by using a developer in which a negatively charged toner is added with a fine silica powder having an average of 10.1 to 5 silica groups on the surface. This is what we discovered.

[Object of the Invention] An object of the present invention is to provide an insulating component developer in which toner charging is stable even in areas where toner consumption is not involved, such as solid white, and a stable image can always be obtained. be.

Another object of the present invention is to provide a developer that has good fluidity, can easily form a thin toner layer on a sleeve, and can provide stable, high-quality images over a long period of time.

[Means and effects for solving the problems] The present invention provides a one-component developer that utilizes triboelectric charging to visualize an electrostatic latent image. This is a developer for electrostatic latent images characterized by adding fine silica powder having an average diameter of 0.1 to 5p. That is, a magnetic substance, a charge control agent 2, a coloring agent, and
A negatively charged toner powder containing an anti-offset agent and other additives dispersed therein is treated with aminosilane and/or amino-modified silicone oil, and has a particle size of 0.1 to 5 µl having 7 amino groups on the surface. This is a developer for electrostatic latent images containing fine silica powder.

In the present invention, the negatively charged toner is alleviated by the positively charged silica fine powder having 7 amino groups added to the negatively charged toner, so that the L charge-up phenomenon can be suppressed. considered to be a thing.

As the silica fine powder used in the present invention, both so-called dry or fumed silica produced by vapor phase oxidation of a silicon halide compound and so-called wet silica produced from water glass can be used.

The aminosilane and amino-modified silicone oil used in the present invention include the following.

Aminosilane is a so-called aminofunctional silane, and is represented by the following general formula.

5SiYn (X is an alkoxy group or chlorine atom 1m is an integer of 1 to 3, Y is a hydrocarbon group having a primary to tertiary amino group, and n is an integer of 3 to 1.) Represented by this general formula Specific examples of aminosilane include the following.

[Example aminosilane 1? H3 1) H2N-CH2CHzNHC:HzC)12cH
2-9i-(QC:H:+)z2) H2N-C0NH
-CH2CH2CH2-Si-(QC2)1s)+3)
HzN-C: H2CH2CH2-3i-(OC2Hs
)+4) H2N-Cl2CH2NHQH2CH2C)
+2-9i-(OCH3h5) H2N-C:H2GH
zC)+2-9i-(OGH3h8) H2N-GHz
CH2NHG)12CH2NHCH2CH2CH2-S
i-(OCH3h7) HsC20COCH2GH2N
HCH2CH2CH2-8i-(OClb)38) H
5G20COCH2CH2HHCH2CIhNHCIh
CHzCH2-9i~(OCRs)3 9) H5C20COCH2CH2NHCH2CIhN
HCHzCH2NHCH2CIh-NHCH2fJ2C
)I2-5i-(OCTo)310) NH2C6H4
-3i-(OCH3)3! I) C6HsNHCToC
H2CH2-Si-(OCH3)3]2) Polyaminoalkyltrialkoxysilanes These aminosilanes are
They may be used alone or in combination of two or more.

Furthermore, amino-modified silicone oil is a silicone oil having 7 amino groups in its side chain, and is generally a silicone oil containing a structural unit represented by formula (I).

-5i-0-...Formula (I) %formula% (Here, R1 is hydrogen, an alkyl group, or an aryl group.

or represents an alkoxy group, and R2 is an alkylene group.

represents a phenylene group, R3 and R4 represent hydrogen, an alkyl group or an aryl group, provided that the above alkyl group,
The aryl group, alkylene group, and phenylene group may contain amino, or may have a substituent such as halogen within a range that does not impair chargeability.) Amino-modified silicon used in the present invention Oil is 25℃
It is preferable that the viscosity at
If it exceeds ps, the dispersion of the amino-modified silicone oil into the fine silica powder becomes insufficient, which tends to cause defective images such as fogging.

Commercially available amino-modified silicone oils include, for example, (I
I) There is an amino-modified silicone oil represented by the formula (where RI, Rs represents an alkyl group, an aryl group, or an alkoxy group, and R2 represents an alkylene group, a phenylene group, or an alkyl group containing amino, R
3 is hydrogen, alkyl group.

m and n representing an aryl group are numbers of 1 or more. ) Specifically, the following are preferred (1), and these may be used alone or in a mixed system of two or more.

5F841? 0-Le Silicone Company 1i
1200 3500KF 393 (
(manufactured by Shin-Etsu Chemical) 60 360KF 8
5? (Manufactured by Shin-Etsu Chemical Co., Ltd.) 70 830
KF 880 (manufactured by Shin-Etsu Chemical) 250
7800KF 861 (manufactured by Shin-Etsu Chemical)
3500 2000KF 8B2 (manufactured by Shin-Etsu Chemical) 750 1900KF H4 (manufactured by Shin-Etsu Chemical) 1700 3800KF
[5 (manufactured by Shin-Etsu Chemical Co., Ltd.) 90 4400
KF 369 (manufactured by Shin-Etsu Chemical) 20
320KF 383 (manufactured by Shin-Etsu Chemical)
20 320X-22-3880 (manufactured by Shin-Etsu Chemical)
90 8800X-22-380 [1 (manufactured by Shin-Etsu Chemical Co., Ltd.) 2300 3800X-22-
38010 (manufactured by Shin-Etsu Chemical) 3500 38
00X-22-38108 (manufactured by Shin-Etsu Chemical) +
300 1700 In addition, the amino equivalent in the present invention is
Att per amino (g/eqi) is the value obtained by dividing the molecular weight by the number of aminos per molecule.

The amount of amino-modified silicone oil added in the present invention is 2 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of fine silica powder. #If the amount of silicone oil is less than 2 parts by weight, the silica fine powder will not be positively charged, and if it is more than 30 parts by weight, silica lumps will easily form during treatment, which is not preferable.

The method of treating fine silica powder with the aminosilane and/or amino-modified silicone oil includes a method of spraying or vaporizing aminosilane, amino-modified silicone oil, or a solution thereof onto the fine silica powder while stirring the fine silica powder, and a slurry method. A method is used in which aminosilane, amino-modified silicone oil, or a solution thereof is added dropwise to the silica fine powder while stirring, or other methods are used. Through such treatment, fine silica powder having amino groups on the surface is obtained.

The volumetric average diameter of the silica fine powder having amino groups on the surface obtained in this way is 0.1 to 5p, preferably 0.5 to 5p.
The range is 4 jars. If the particle size is too large (5 μm or more), it will be difficult to obtain sufficient fluidity as a component toner, and if the particle size is too small (0.1 μm or less), silica particles with amino groups on the surface will be difficult to obtain. The powder covers the toner surface and the toner tends to become positively charged.
This is not preferable because it causes problems such as fog or low density f.

To measure the particle size of the silica fine powder according to the present invention,
Various conventional particle size distribution measuring devices cannot be used. The most preferable device is a device that measures the number and volume of particles by dispersing particles in a conductive liquid and amplifying the change in electrical resistance of the liquid that occurs when the particles pass through pores. 0 particles are dispersed in 0.1% saline and measured using a 30 gm aperture.

Further, the amount of the fine silica powder having an amino group on the surface added to the negatively charged toner is 0.105 to 2.0% by weight, preferably 0.1 to 1.0% by weight. If the amount added is too small (less than 0.05% by weight), the necessary fluidity cannot be obtained, and if it is too large (below 2.0% by weight), the toner becomes positively charged, resulting in fogging, decreased density, etc. This is because it causes harm.

The negatively charged toner used in the present invention is easily prepared by a known method.

As the binder resin for the toner, homopolymers of styrene and its substituted products, such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymer, and styrene-vinyltoluene copolymer, and copolymers thereof are used. Copolymerization: Copolymers of styrene and acrylic esters such as styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-n-butyl acrylate copolymer; Styrene-methyl methacrylate copolymer Copolymers of styrene and methacrylic esters such as styrene-ethyl methacrylate copolymer, styrene-n-butyl methacrylate copolymer; multi-component copolymers of styrene and acrylic esters and methacrylic esters; Others: styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Styrenic copolymers of styrene and other vinyl monomers such as; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin,
Polyvinyl butyral, polyacrylic acid, phenolic resin, aliphatic or alicyclic hydrocarbon resin 9 petroleum resin, chlorinated paraffin, etc. can be used alone or in combination.

In particular, binder resins for toners used in pressure fixing systems include low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymers, ethylene-acrylic acid ester copolymers, higher fatty acids, polyamide resins, polyester resins, etc. can be used alone or in combination.

The polymer, copolymer, or polymer blend used is a vinyl aromatic or acrylic polymer represented by styrene. More desirable results can be obtained when the content is less than Ovt% hI7)ffi.

Any suitable pigment or dye can be used as a colorant in the toner, such as carbon black.

There are known dyes and pigments such as iron black, phthalocyanine blue, gun blue, quinacridone, and benzidine yellow.

When the toner is a magnetic toner, a ferromagnetic element such as iron, cobalt, or nickel, or iron such as magnetite, hematite, or ferrite is used.

It may contain a magnetic material such as an alloy or compound of cobalt, nickel, or manganese, or other ferromagnetic alloy.

Additives may be mixed with the toner as necessary. An example of such an additive is Teflon.

Examples include a lubricant such as zinc stearate, a fixing aid (for example, low molecular weight polyethylene), and a metal oxide such as tin oxide as a conductivity imparting agent.

Further, any charge control agent can be used in the toner, but in view of the gist of the present invention, negatively charged ones such as metal-containing azo dyes and metal-containing salicylic acid compounds are preferable. Regarding the particle size of the toner, those in the usual range can be used, but in a toner with a volume average diameter of 11 to 12 g, particles of 4 l or less are
~8% or less, preferably with less ultrafine powder.

(Number distribution per coulter counter measurement) As described above, the toner (developer) containing fine silica powder having 7 min groups on the surface of the present invention can be used particularly in a one-component development method using a developing device having a suppressing member. Even if there is a continuous white background, such as solid white, so-called charge-up does not occur, and stable images can be obtained even after long-term use.

[Example] The basic configuration and features of the present invention have been described above, and the method of the present invention will be specifically explained based on Examples below. However, this does not limit the embodiments of the present invention in any way. Parts in the examples are parts by weight.

Example 1 The above mixture was kneaded at 150° (!-180°C) with a roll mill, and after cooling was subjected to jet mill pulverization and air classification by a well-known method to obtain a mixture containing 5% of fine particles with a volume average diameter of 4 g or less. A classified magnetic toner product was obtained.

Next, particle size 1. 5 parts of γ-aminoprobyltriethoxysilane diluted with a solvent was sprayed onto 100 parts of +p silica fine powder and dried to obtain a silica fine powder having 7 amino groups on the surface. A toner was obtained by adding and mixing 0.4 part of this treated silica fine powder to 100 parts of the above toner.

Using this toner, a commercially available copying machine Selex 60AZ
When the development was carried out using a modified developing device to perform toner coating with a pressing member (see Figure 1), a good image without fog with an image density of 1.3 to 1.4 was obtained. Ta. After this, I copied 100 solid self-portraits, and when I printed the images immediately after, the image density was still 1.3 to 1.4.
It was good.

Also, I conducted a durability test on too many sheets using this toner and device, and the image density was 1.3 to 1 from beginning to end.
, 4, which was stable, and there were no other problems such as fogging.

Example 2 Instead of γ-7 minopropyltriethoxysilane-treated silica fine powder, 100 parts of silica fine powder with an average particle size of 3 l was added to amino-modified silicone oil (Shin-Etsu Chemical type KF-857).
) A toner was obtained in the same manner as in Example 1 except that 0.6 parts of silica fine powder having an amino group on the surface treated with 10 parts was used. Next, the same tests as in Example 1 were conducted. , the image density was 1. before and after taking 100 solid self-portraits.
Good images with no fog were obtained in the range of 3 to 1.4. or,
There were no problems with the durability test of 10,000 sheets.

Comparative Example 1 A toner was obtained in the same manner as in Example 1, except that 0.3 parts of commercially available silica fine powder R-972 (manufactured by Nippon Aerosil Co., Ltd.) was used instead of the silica fine powder in Example 1, and the same test was carried out. When I went there, I found that the image density was 1.3-1.0 before taking a solid self-portrait.
4, but after 100 solid white sheets, the image density decreased to 1.0.

Comparative Example 2 The silica having 7 amino groups on the surface used in Example 2 was
A toner was prepared in the same manner as in Example 2, except that 2.2 parts was added, and then the same test was conducted.The image density before and after solid white remained unchanged, but the image density was around 1.2. Yes, fog appeared on the copy paper.

Example 3 Average diameter of 2.5μ instead of treated silica fine powder of Example 1
A toner was prepared in the same manner as in Example 1, except that 0.8 parts of 100 parts of silica fine powder treated with 15 parts of silicone oil KF-885 (manufactured by Shin-Etsu Chemical) having an amino group in the side chain was added. Then, when a similar test was conducted, the image density did not change even after 100 solid self-portraits, and the image density was 1.3.
Met. Moreover, there were no problems in the durability test of 10,000 sheets.

Comparative Example 3 Instead of the treated silica fine powder of Example 1, the average particle size was 5.5.
A toner was prepared in the same manner as in Example 1, except that 1.0 part of silica powder treated with 5 parts of γ-aminopropyltriethoxysilane was added to 100 parts by weight of the pot's fine silica powder, and the same test was conducted. The image density of around 100 sheets of solid white remained unchanged at about 1.3, but in a durability test of 4000 sheets, band-like unevenness appeared, which was thought to be due to poor fluidity.

[Brief explanation of the drawing]

FIG. 1 shows an example of a developing device. l...Toner, 2...Developing sleeve,
3... Magnet, 4... Suppression member, 5...
... Suppressing member holding member, 6... Toner hopper 7...
・Photoreceptor.

Claims (1)

[Claims] (1) In a one-component developer that uses triboelectric charging to visualize electrostatic latent images, fine silica powder with an average diameter of 0.1 to 5 μm and having amino groups on the surface is added to negatively charged toner. A developer for electrostatic latent images characterized by: