JPH04175769A - Color developer - Google Patents

Abstract

PURPOSE:To stabilize the electrification property in various environments and obtain a high-quality image by containing a color toner containing a specific external additive and a carrier having a specific additional component in coat resin. CONSTITUTION:A insulating nonmagnetic color toner containing colorant- containing resin grains and a flow improving agent and a carrier with the average grain size 10-100mum coated with electrically insulating resin 0.1-5wt.% against the carrier core material weight are contained. A nitrogen-containing compound 0.3-15wt.% containing 3-30 carbon atoms is contained against the whole coating resin, and this organic resin made of a fluoroalkyl acrylic polymer is coated on a carrier core material to obtain the carrier. The low flow improving agent with the absolute value 30muc/g or below against the carrier is used. The friction electrification characteristic is stable, and carrier sticking is excellently prevented.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a developer used for developing an electrical latent image or a magnetic latent image in electrophotography or electrostatic printing, and particularly relates to a developer used for developing an electric latent image or a magnetic latent image in electrophotography or electrostatic printing. This invention relates to a color developer that has significantly improved image quality.

[Prior Art] In conventional electrophotography, the j'1 method of developing an electrostatic latent image using toner can be roughly divided into two methods: a method using a so-called two-component developer in which a small amount of toner is dispersed in a medium called a carrier; There are two methods: (1) using a toner without using a carrier, and (4) using a loose-component developer. The present invention relates to a two-component developer comprising a toner and a carrier among manual developers. The carriers constituting the two-component developer are roughly divided into conductive carriers and insulating carriers.In the case of conductive carriers, oxidized or unoxidized iron powder is usually used. The developer has the disadvantage that its triboelectric charging properties with respect to the toner are unstable and that fog occurs in the visible image formed by the developer. That is, as a developer is used, toner particles adhere and accumulate on the surface of iron powder carrier particles (spent toner), which increases the electrical resistance of the carrier particles, lowers the bias current, and causes triboelectrification. As a result, the image density of the visible image formed drops suddenly and fog increases or disappears. Therefore, using a developer containing iron powder
When copying is carried out continuously using an L-go copying apparatus, the developer deteriorates after a few copies, so it is necessary to replace the developer at the W period, resulting in high costs.

Further, typical insulating carriers are carriers in which the surface of a carrier core material made of a ferromagnetic material such as iron, nickel, or ferrite is uniformly coated with an insulating resin. In the developer using this gear, there is significantly less toner particles on the gear surface than in the case of a conductive gear, and at the same time it is easy to control the frictional electrification between the roller and the carrier. It has the advantage of being particularly suitable for high-speed electronic copying machines because of its excellent durability and long service life.

However, in this insulating carrier, the carrier itself is strongly charged with a polarity opposite to that of the toner particles.
Not only does this cause the problem of old paint adhering to the back plate, but also the amount of toner spent on the carrier surface increases.

This tendency is noticeable in non-magnetic color (-toners) which do not have leakage No. 1~ in the toner itself, and is especially noticeable in toners that use colorant-containing resin particles using a Bossester binder with high 4J tea power. , and becomes a problem especially under low humidity.

As a countermeasure for gear rear sight binding, in order to eliminate the gear rear adhesion that occurs because the gear rear itself is strongly IF fitted, conductive carbon black or the like is dispersed in the coating resin and coated on the carrier. has been proposed, but so far it has not necessarily been possible to achieve a stable coating state, and problems such as fogging have occurred due to the release of carbon black and other substances due to long-term use. I'm here.

Furthermore, examples have been proposed in which carriers are coated with fluororesin or silicone resin, which have low surface energy, but carriers coated with resins with low surface energy have a slow rise in toner fit, especially when toner is coated under crystal sludge. The current situation is that there are still no satisfactory results due to scattering and other problems.

"Problems to be Solved by the Invention" The present invention provides a developer free from the above-mentioned drawbacks, and provides a color developer that has stable triboelectric charging properties and is excellent in preventing carrier adhesion. It is something.

Another object is to provide a color developer with less toner scattering.

Another purpose is toner pen on the surface of carrier particles]
It is an object of the present invention to provide a long-life color developer that is less likely to occur and has a stable developing ability due to the strong adhesion of the carrier coating resin.

Another purpose is to respond to changes in the environment! The object of the present invention is to provide a color developer that has a good charge rise, small fluctuations in ft characteristics, and provides extremely stable images.

[Means and effects for solving the problems] The present invention is characterized in that an insulating non-magnetic color toner containing at least colorant-containing resin particles and a flow improver and a gear rear core material of 0. A color developer comprising a carrier having a weight average particle diameter of 10 to 100 μm coated with 1 to 5.0% by weight of an electrically insulating resin, (1) The carrier is in an organic resin comprising a fluorinated alkyl acrylic polymer. In this case, the carrier core material is coated with a resin containing 0.3 to 15% by weight of a nitrogen-containing compound containing 3 to 30 carbon atoms per one atomic number of nitrogen, based on the total coating resin. (1) The flow improver is a low tribo flow improver having an absolute value of 30 μc/g or less relative to the carrier.

Until now, as an example of using a compound containing a nitrogen atom as a coating material for a carrier, for example,
No. 124345, etc., proposes an example of a compound having an amine structure containing a tertiary amine as a charge control agent.

However, with the above carrier configuration, when the non-magnetic color toner of the present invention is combined with an insulating non-magnetic color toner that does not have a conductive member such as magnetic powder or carbon black, although the initial characteristics are certainly good, the long-term It has been found that the initial level cannot always be maintained during continuous copying over a long period of time, resulting in problems such as a decrease in image density and deterioration of fog.

Furthermore, an example of containing N-vinylcarbazoles has been proposed in JP-A-59-124346, etc.
The above example is a carrier for a positive toner, and is completely different from the present invention.

In addition, attaching a quaternary ammonium salt as a compound having an ammonium salt structure to the carrier surface has been disclosed in, for example, Japanese Patent Application Laid-open No. 62-229256, but the above proposal does not involve incorporating it into the resin. This is completely different from an invention.

Furthermore, the use of fluorinated alkyl acrylic polymers as coating materials for carriers was disclosed in Japanese Patent Application Laid-Open No. 61-80.
These fluorinated alkyl acrylic polymers have significant advantages such as adhesion to the core material, as disclosed in Japanese Patent Application Laid-open No. 163 and Japanese Patent Application Laid-Open No. 62-39881. However, changes in the amount of charge due to environmental differences, especially changes in humidity, are quite large, and with high humidity, when an original document with a high image area ratio is continuously copied, sufficient charge is not applied and toner scatters, resulting in unsatisfactory results. It's not something I can do.

The reason why a carrier made of a fluorinated alkyl acrylic polymer coated with a compound containing a nitrogen atom that is charged with the opposite polarity to that of the toner is extremely effective in stabilizing charging is because it has a lower surface energy than the fluororesin toner. This is because the above-mentioned compound compensates for the slowness of charging.

Furthermore, it has been found that a carrier containing an ammonium salt also plays a role in lowering the absolute value of triboelectricity under low humidity.

Although the reason for this is not entirely clear, it is presumed that the nitrogen compound contained in the present invention creates leak sites in response to the phenomenon of toner charge-up.

In the present invention, in order to make the above-mentioned charging rise function and leakage function sufficiently effective, the nitrogen-containing compound must have 3 to 30 carbon atoms, preferably 6 to 24 carbon atoms per nitrogen atom. It is necessary to contain

If the number of carbon atoms is less than 3, the moisture resistance properties, especially under high temperature and high humidity conditions, will deteriorate, and problems such as toner scattering due to triboelectric deterioration will occur.

In addition, if the number of carbon atoms is more than 30, the characteristics under high temperature and high humidity will improve, and the charging start-up will also be good, but the leakage function will decrease, and as a result, image density will decrease due to increased triboelectricity under low temperature and low humidity. A problem will occur.

As the nitrogen-containing compound used in the present invention, general compounds such as a compound having an amine structure and a compound having a pyridine ring structure can be used.

A particularly preferred compound for the present invention is a compound having an amine structure, and is represented by the following formula 1.

Specific examples of nitrogen-containing compounds that can be used in the present invention are shown below.

(The following is a blank space.) 〉 Examples of monomers for the fluorinated alkyl acrylic polymer, which is the carrier coating resin of the present invention, include the following.

That is, 1,1-dihydroperfluoroethyl, 1,1-dihydroperfluoropropyl, 1,1-dihydroperfluorohexyl, 1,1- of acrylic acid or methacrylic acid.
Dihydroperfluorooctyl, 1,1-dihydroperfluorodecyl, 1,1-dihydroperfluorolauryl, 1
．． 1,2.2-tetrahydroperfluorobuty) Ii, 1
, 1,2.2-tetrahydroperfluorohexyl, 1.
1,2.2-tetrahydroperfluorooctyl, 1. i
+ 2.2-tetrahydroperfluorodecyl,! ,i
, 2.2-tetrahydroperfluorolauryl, 1.1.
2.2-tetrahydroperfluorostearyl, 2,2,
3.3-tetrafluoropropyl, 2,2,3,3,4.
4-hexafluorobutyl, 1,1. ω-trihydroperfluorohexyl, 1,1. ω-trihydroperfluorooctyl, 1,1,1,3,3.3-hexafluoro-2
Examples include ester compounds such as -fluoropyl, 3-perfluorononyl-2-acetylpropyl, and 3-perfluorolauryl-2-acetylpropyl.

Further, other suitable resin components to be copolymerized with the above-mentioned fluorinated alkyl acrylic monomer include the following. That is, alkylstyrenes such as styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, fluorostyrene, chlorostyrene, bromostyrene, Halogenated styrenes such as dipromostyrene and iodostyrene, and styrenic monomers such as nitrostyrene, acetylstyrene, and methylstyrene: acrylic acid,
Methacrylic acid, α-ethyl acrylic acid, crotonic acid, α
- Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as methylcrotonic acid, α-ethylcrotonic acid, isocrotonic acid, tiglic acid, ungellic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid,
Examples include addition-polymerizable unsaturated aliphatic dicarboxylic acids such as dihydromuconic acid.

The carrier coating polymer only needs to contain a fluorinated alkyl acrylic polymer.

In the present invention, all general materials such as iron powder and ferrite powder can be used as the carrier core material.

The coating amount of the coating resin according to the present invention to the carrier core material is such that the resin solid content is O, 1 wt% to 30 wt%, preferably 0.2 wt% to 10 wt%. If the amount of O is less than 1 wt%, the coating effect of the resin of the carrier core material will not be sufficient, and if the coating amount exceeds 30 wt%, it is meaningless, and from the viewpoint of manufacturing, too much resin may be present alone, so it is preferable. do not have.

In the present invention, all common carrier core materials such as iron powder and ferrite powder can be used, and this is also one of the major features of using resin. Also,
The particle size of the carrier core material used is 10 to 100 μm, preferably 20 to 60 μm.

In particular, the material of the magnetic particles used in the present invention is 9
8% or more Cu-Zn-Fe (metal composition ratio (5-20)
Ferrite particles having a composition of: (5 to 20) : (30 to 8o) are preferable because the surface can be easily made uniform and the fit ability is stable.

As the flow improver used in the present invention, the above-mentioned! Any material may be used as long as it satisfies the electrical properties.

For example, inorganic oxides such as silica, alumina, titanium oxide, zirconium oxide, boron nitride, and silicon carbide may be used as they are or may be surface-treated to a desired amount of charge.

Suitable for the present invention are titanium oxide and alumina, which can relatively easily obtain a sharp particle size distribution, and particularly suitable is titanium oxide, which has the same polarity as the toner.

Although there are no particular restrictions on its manufacturing method or crystal structure, titanium oxide manufactured from titanium alkoxide by a gas phase method of 500 mm or less is particularly suitable because it has a sharp particle size distribution and high sphericity.

Specific examples of the titanium alkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, titanium tetrabutoxide, and jetoxytitanium oxide.

In particular, in the present invention, as an additive, an average particle size of 20
~200mμ, preferably 20-150mμ and 300~
Specific electrical resistance 106~ with two peaks at 800 mμ
It is even more effective to externally add positive IF conductive organic resin particles having a resistance of 1014 Ωm.

The reason for this is that the charge-up caused by excessive rubbing between the binder resin and the carrier used in the present invention is further neutralized by the organic resin particles.

Furthermore, by adding these organic resin particles, the rise of the %F charge of the toner is further promoted, and very stable charging characteristics are achieved from the initial stage.

Binding substances used in the colorant-containing resin particles used in the present invention include polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-'70 styrene copolymer, styrene vinyltoluene copolymer, etc. homopolymers of styrene and its substituted products; copolymers thereof; styrene-methyl acrylate copolymers, styrene-methyl acrylate copolymers;
Copolymers of styrene and acrylic esters such as ethyl acrylate copolymer and styrene-butyl acrylate copolymer; styrene-methyl methacrylate copolymer,
Copolymers of styrene and methacrylic esters, such as styrene-ethyl methacrylate copolymer and styrene-n-butyl methacrylate copolymer: Multi-component copolymers of styrene and acrylic esters and methacrylate/l/M 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 @-type; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin,
Polyvinyl butyral, polyacrylic acid, phenolic resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. can be used alone or in combination. In particular, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, polyester resin, etc. are used as binder resins for toners used in pressure fixing systems. Can be used alone or in combination.

A particularly preferred resin for carrying out the present invention is styrene-
There are acrylic ester resins and polyester resins.

In particular, the following formula (wherein R is ethylene or propylene group, x, y
are each an integer of 1 or more, and the average value of A polyester resin that is cocondensed with at least a lower alkyl ester and a carboxylic acid component (for example, fumaric acid, maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) has sharp melting characteristics. It is more preferable because it has the following.

In particular, in terms of permeability in trapene, the apparent viscosity at 90°C is 5xlO' to 5x10'bois, preferably 25
X10' to 2X10' voids, more preferably 105 to
106 voids, and the apparent viscosity at 100°C is 10
4-5xlO' voice, preferably 104-3.0X1
When the void is 0', more preferably from 10' to 2×105, a color HP with good transparency can be obtained, and even as a full color toner, good results can be obtained in fixing properties, color mixing properties, and high temperature offset resistance.

In particular, the absolute value of the difference between the apparent viscosity P1 at 90°C and the apparent viscosity P2 at 100°C is 2X105<I PI
It is preferable that P2 1 <4X 10'.

A charge control agent may be added to the toner according to the present invention in order to stabilize the charging characteristics. In this case, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferable. In the present invention, the present invention becomes even more effective when a negatively charged developer is used, and the negative charge control agent at that time may be, for example, a metal complex of alkyl-substituted salicylic acid (for example, Z-T).
Examples include organometallic complexes such as chromium complexes or zinc complexes of art-butylsalicylic acid. When a negative charge control agent is blended into the toner, it is 0.1 to 0.1 to 0.1 to 100% by weight of the binder resin; O3! Parts by weight, preferably 0.5 to 8! ! It is best to add a certain amount.

When preparing a two-component developer by mixing with the toner according to the present invention, the mixing ratio is 2 as the toner concentration in the developer.
．． Good results are usually obtained from 0% to 12% by weight, preferably from 31% to 9% by weight. Toner density is 2
If it is less than .01% by weight, the image density will be low and it will not be practical.
If it exceeds 2% by weight, fogging and in-machine scattering will increase, and the useful life of the developer will be shortened.

As the colorant used in the present invention, a wide variety of known dyes and pigments can be used, such as phthalocyanine blue, industhrene blue, peacock blue, permanent red, lake red, rhodamine lake, banza yellow, permanent yellow, benzidine yellow, etc. . Its content is preferably 0.5 to 9 parts by weight.

The method for measuring the amount of triboelectric charge in the present invention will be described below.

The measurement method will be explained in detail using drawings.

=X diagram is an explanatory diagram of an apparatus for measuring the amount of triboelectric charge of toner. First, 50 g of a mixture of toner and carrier whose weight ratio is 1:19 is placed in a metal measuring container 22 with a 500-mesh screen 23 at the bottom.
was placed in a polyethylene bottle having a capacity of 50 to 100,100 O, shaken by hand 30 times and 500 times, and about 0.5 to 0.9 g of the mixture (developer) was added and the metal lid 24 was closed. Weigh the entire weight of the measurement container 22 at this time, W+(g
). Next, in the suction device 21 (at least the part in contact with the measurement container 22 is an insulator), suction is performed from the suction port 27, and the air volume control valve 26 is adjusted to raise the pressure of the vacuum gauge 25 to 250.
Let it be mmAq.

In this state, suction is applied for a sufficient period, preferably about 2 minutes, to remove the toner. The potential of the electrometer 29 at this time is assumed to be V (volt). Here, 28 is a capacitor, and the capacitance is C (μF). In addition, the weight of the entire measurement container after suction is measured and is defined as W2 (g). The amount of triboelectric charge of this toner (
μc/g) is calculated as shown below.

[Example] Hereinafter, parts mean parts by weight.

Example 1 100 parts of a 20 wt% toluene solution of 1.1-dihydroperfluorooctyl methacrylate copolymer and 20 parts of a 5.0 wt% methanol solution of the N atom-containing compound shown in Exemplary Compound (III) were thoroughly mixed with a stirrer. A carrier N solution was prepared by stirring until the solution was mixed.

Apply this coating solution using a coating machine (Nispira Coater manufactured by Kaida Seiko Co., Ltd.)
It was applied to spherical ferrite particles of Cu-Zn composition with an average particle size of 45 μm.

The obtained coated carrier was dried at 60° C. for 1 hour to remove the solvent, and then heated at 140° C. for 1 hour to obtain a resin-coated carrier.

The resin coating amount of the obtained carrier was 0.61 wt%, and observation using an electron microscope confirmed that the ferrite core material was uniformly coated with the resin.

On the other hand, the mixture was slightly mixed with a Henschel mixer, melted and kneaded with a twin-screw ratio kneader, and after cooling, coarsely pulverized with a hammer mill to about 1 to 2 mm, and then pulverized with an air jet type pulverizer. It was finely pulverized. Furthermore, the obtained finely pulverized product is classified to have the particle size distribution of the present invention.
~10 μm was selected to obtain colorant-containing resin particles.

Titanium tetraisopropoxide with a charge amount of -3.6 μc/g was gas-phase decomposed at 350 tons on the resin particles, and 0.7 part of titanium oxide with a BET of 120 m2/g was added, and the average particle size was 55 μm! A cyan toner was prepared by adding 0.3 part of styrene/methyl methacrylate resin particles having a coulometric capacity of +9° μc/g.

In addition, this carrier and cyan toner were mixed at a toner concentration of 5%.
to prepare a developer and set the development contrast to 300.
Using a color copying machine CLC-500 (manufactured by Canon) fixed at
Table 1 shows the results of printing 20,000 images at 80%. It can be seen from Table 1 that the above-mentioned developer exhibits small fluctuations due to environmental changes and is very good.

Note that the following comparative examples and examples are also shown in Table 1.

Image development was carried out in the same manner as in Example 1 except that the N atom-containing compound was not used in Example 1.
%, the image density decreased to 1.20.

Comparison 11 Example 1 was carried out except that silicic acid fine powder (BET 170 m2/g, charge amount -7.5 μc/g) which had been subjected to hydrophobization treatment with dimethyldichlorosilane was used instead of using titanium oxide. When image printing was carried out in the same manner as in Example 1, the image density decreased to 1.14 at 20° C./10%.

Comparative Example 3 When image printing was carried out in the same manner as in Example 1 except that titanium oxide was not used, the initial results were good, but after about 500 sheets, toner scattering was severe and G+ value was discontinued. .

Huni, Kata - 21 In Example 1, image printing was carried out in the same manner as in Example 1 except that resin particles of opposite polarity to the toner were not used, and the overall image density was lower than in Example 1. Low, especially 20℃/
At 10% lower, 01-02 was low, but good results were obtained.

Thick layer side 3 Imaging was carried out in the same manner as in Example 1, except that titanium oxide (BET 9om'/g, charge amount -12 μe/g) was used, which was obtained by hydrophobicizing titanium oxide with a titanium coupling agent. When I carried out step 2, good results were obtained.

100 parts of a 20 wt% toluene solution of 1,1,2,2-tetrahydroperfluorobutylprobylstyrene copolymer and 5.0 wt of the N atom-containing compound shown in Exemplary Compound (1)
A carrier was prepared and imaged in the same manner as in Example 1 except that 20 parts of % methanol solution was used.
Although the durability characteristics below /80% were slightly deteriorated, good results were obtained.

(The following is a blank space) [Effects of the Invention] The present invention provides stability in chargeability in various environments using a color developer containing a color toner having a specific external additive and a carrier having a specific additive component in the coating resin. image quality and obtain high-quality images.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an apparatus for measuring the amount of triboelectric charge of toner.

Claims (4)

[Claims] (1) Weight average particle size of an insulating non-magnetic color toner containing at least a colorant-containing resin particle and a flow improver and coated with an electrically insulating resin of 0.1 to 5.0% by weight based on the weight of the carrier core material. A color developer comprising a carrier having a diameter of 10 to 100 μm, [1] The carrier contains 3 to 30 carbon atoms per nitrogen atom in an organic resin made of a fluorinated alkyl acrylic polymer. A carrier in which a carrier core material is coated with a resin containing a nitrogen-containing compound in an amount of 0.3 to 15% by weight based on the total coating resin;
A color developer characterized in that it is a low tribo flow improver having an absolute value of g or less. (2) The color developer according to claim 1, wherein the fluidity improver is titanium oxide or alumina. (3) The color developer according to claim 1, wherein the fluidity improver is titanium oxide that is charged to the same polarity as the toner. (4) The flow improver is made of titanium alkoxide.
The color developer according to claim 1, wherein the color developer is an amorphous spherical titanium oxide obtained by a gas phase pyrolysis reaction at a temperature of 0° C. or lower and charged to the same polarity as the toner.