JPH03236064A - Positively charged toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To lessen the deterioration with lapse of time and environmental deterioration and to obtain a better electrostatic charge characteristic by adding powder of a specific basic material to toner particles contg. a resin and a coloring agent. CONSTITUTION:Basic magnesium, aluminum and hydroxy carbonate powder are added to the toner particles contg. at least the resin and coloring agent. This coloring agent consists of a dye or pigment of the corresponding color and is incorporated at 3 to 20 pts. wt. into 100 pts. wt. resin. The need for using a charge control agent is eliminated if the resin having the high tendency to charging positive is used. The good electrostatic performance is obtd. in this way and good images are obtd. even under the use conditions under which the staining of copies and the degradation in image density at and under a high temp. and high humidity or at the time of continuous copying is lessened.

Description

[Detailed Description of the Invention] Industrial Application Fields> The present invention relates to a positively chargeable toner for developing electrostatic images used in fields such as electrophotography, and more specifically, toner for developing electrostatic images containing a specific substance. The present invention relates to a positively chargeable toner for development.

<Prior Art> In the development process, a developer used in an electrophotographic method such as an electronic copying machine is first attached to an image carrier such as a photoreceptor on which an electrostatic image is formed, and then After being transferred from the photoreceptor to transfer paper in the transfer process, it is fixed on the copy paper surface in the fixing process. At that time, the developer for developing the electrostatic charge image formed on the latent image holding surface is a two-component developer consisting of a carrier and toner, and a one-component developer (magnetic toner) that does not require a carrier. It has been known.

The toners contained in the developer include positively chargeable toners and negatively chargeable toners, and conventionally, nigrosine dyes, quaternary ammonium salts, etc. have been added to toners to impart chargeability to positively chargeable toners. Charge control agents as agents and coating agents that impart desired chargeability to carriers have been known.

<Problems to be Solved by the Invention> However, the effect of imparting chargeability of these conventional charge control agents is not necessarily satisfactory. It is difficult to obtain a toner that exhibits favorable change and good morphology, and image stains such as fogging occur under high temperature and high humidity conditions or during continuous copying.
Another problem is that a stable copy density cannot be obtained.

Since resin, which is the main component of toner, has a strong tendency to be negatively charged except for some types, it is difficult to obtain a positively chargeable toner that always exhibits a constant and sufficient charging ability.

When an electrostatic image developer is used, it is agitated and triboelectrically charged by contact with a charging medium such as a carrier or a charging blade, but especially in the case of a positively chargeable toner, the developer is stirred and charged by friction when it comes into contact with a charging medium such as a carrier or a charging blade. When restarting the use of the device, there was a problem that the charging did not rise properly when the developer started stirring, and the electrostatic attraction force with the charged medium was insufficient, causing toner to scatter inside the device. . The phenomenon of toner scattering caused by the slow rise in charging of the toner becomes particularly noticeable at high temperatures and/or under high temperature conditions.

As a result of intensive studies to solve this problem, the present inventors discovered that by adding a specific substance to positively chargeable toner particles, a toner exhibiting preferable charging characteristics and excellent image quality could be obtained. The invention has been achieved.

That is, an object of the present invention is to provide a positively chargeable toner for developing electrostatic images, which exhibits less deterioration of image quality over time and environment, and has excellent charging characteristics.

<Means for Solving the Problems> Therefore, the object of the present invention is to provide toner particles containing at least a resin and a colorant, and basic magnesium.
This can be easily achieved using a positively chargeable toner for developing electrostatic images, which is characterized by containing aluminum hydroxy carbonate hydrate powder.

<Function> As the resin component that can be used in the present invention, various known resin components that can be used in a toner for developing an electrostatic image can be used. For example, styrene resin, styrene acrylic copolymer resin,
There are polyester resins, epoxy resins, mixed resins thereof, and resins having amine groups in their alkyl side chains, among which styrene or polyester resins are preferred.

The colorant used in the present invention is not particularly limited as long as it is conventionally used, and carbon black or the like is used to obtain a black toner. Also,
In the case of color toners such as blue, red, yellow, etc., a coloring agent consisting of a dye or pigment of the corresponding color is used.

The content of the colorant is 3 to 20 parts by weight per 100 parts by weight of the resin.
Preferably, it is expressed in parts by weight.

The toner of the present invention does not necessarily need to contain a positive charge control agent if a resin with a strong tendency to be positively charged, such as styrene-diethylamine ethyl methacrylate copolymer, is used as a material, but it is not necessary to contain a positive charge control agent. As with the toner, it is preferable to include a charge control agent depending on the chargeability required depending on the device including the photoreceptor and the type of carrier.

The charge control agent can be selected from a wide range of known ones, including quaternary ammonium salts, nigrosine dyes, imidazole derivatives and metal complexes thereof, as detailed below.

(2) Quaternary ammonium salts Specific examples include compounds represented by the soft formula (I) or (n).

... (1) (In the formula, R' represents an alkyl group having 1 to 8 carbon atoms, and R2
and R3 each represent an alkyl group having 1 to 18 carbon atoms, and R4 represents an alkyl group having 1 to 8 carbon atoms or a benzyl group. ) ... (If) (wherein, R1 represents an alkyl group having 12 to 22 carbon atoms,
R2 and R3 each represent an alkyl group having 1 to 5 carbon atoms, R4 represents an alkylene group having 1 to 5 carbon atoms, and R3
represents a para-substituted phenyl group having an alkyl group having 1 to 6 carbon atoms or an alkyl group having 1 to 3 carbon atoms, and n represents 3 or 4.

) Regarding (f), More specifically, for example, the following Examples include hardware.

(1-1) ... (1-2) ... (1-8) ... (I-9> (1-10) (U) Regarding More specifically, for example, the following Examples include compounds.

... (1-4) ... (1-5) (■ 6) (■ -D) ■ Nigrosine dyes Specifically, for example, Bontron N series manufactured by Orient Chemical ■, Orient Subirino Tobrasoku AB , Orient Spirit Toph Rank SB, Orient Black BS
, Solvent blank #5゜Nigrosine hese Eχ
, Solgento Black #7゜Spirit Black Nα850 manufactured by Sumitomo Chemical ■. Examples include Spirit Black Nα900.

(2) Triphenylmethane compound Specific examples include compounds represented by -soft formula (III).

(In the formula, R represents an alkyl group having 1 to 5 carbon atoms, preferably a methyl group.) (1) Imidazole derivatives Specific examples include compounds represented by -soft formulas (IV) and (V).

(In the formula, R', R2, and R3 each represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group.) 2 2 (In the formula, R1, Rz, and R3 each represent a hydrogen atom, and an alkyl group having 1 to 20 carbon atoms. 20 alkyl group, aralkyl group or aryl group) Alternatively, a polyamine resin or a plurality of charge control agents may be used in combination.

In general formula (IV), substituents R', R2, and R3 include hydrogen atoms; branches such as methyl, ethyl, propyl, butyl, hexyl, nonyl, undecyl, F-decyl, and heptadecyl groups; Alkyl group which may be substituted; aryl groups such as phenyl group, naphthyl group, anthryl group, phenanthryl group, and pyrenyl group are used.

- Typical specific examples of imidazole derivatives represented by the soft formula (■) include the following.

(Compound examples) - In the soft formula (V), the substituents R1, R2, and R3 are hydrogen atoms; methyl group, ethyl group, propyl group, butyl group, hexyl group, nonyl group, undecyl group, to'decyl group, heptadecyl group Alkyl groups that may be branched such as groups; aralkyl groups such as benzyl, phenethyl, and methylbenzyl groups; aryl groups such as phenyl, naphthyl, anthryl, phenanthryl, and pyrenyl groups are used.

Typical specific examples of the imidazole derivative represented by the general formula (V) include the following.

(Compound Examples) ... (V-10) Generally, the compound represented by the soft formula (IV) or (V) above has an average particle size of 0.01 to 10 μm, preferably 0.01 to 10 μm.
It is preferable to adjust the toner with a particle size in the range of 1 to 5 μm.

Methods for incorporating the above compound into the developer include a method of adding it inside the developer and a method of adding it externally. When internally added, the amount of these compounds used is usually 0.1 to 20 parts by weight, preferably 0.5 to 20 parts by weight, per 100 parts by weight of the resin.
It is used in a range of 10 parts by weight.

In addition, when adding externally, 0.0 parts by weight per 100 parts by weight of resin.
1 to 10 parts by weight is preferred.

(2) Metal complexes of imidazoles Specific examples include metal complexes of imidazoles represented by the following soft formula (Vl).

R' (In the formula, R1, R2, and R3 each represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group.) In the general formula (■), the substituents R', R'', and R3 are as follows: Hydrogen atom; methyl group, ethyl group, propyl group,
Alkyl groups that may be branched such as butyl, hexyl, nonyl, undecyl, dodecyl, heptadecyl; aryl groups such as phenyl, naphthyl, anthryl, phenanthryl, pyrenyl are used. .

Examples of metal atoms in the complex include zinc, copper, nickel, cobalt, lead, and chromium, and among these, zinc is particularly preferred.

The metal complex used in the present invention can be synthesized by various known methods. That is, the imidazole represented by the soft formula (■) above is dissolved in water, alcohol, ether, etc., and various metal salts and the like are mixed as a metallizing agent in a molar ratio of 2:1. Next, the mixture is heated, a pH adjuster is added to carry out a reaction, and the precipitate is collected by filtration, thoroughly washed, and dried.

Generally, the above compound has an average particle size of 0.01 to 10 μm,
It is more preferable to prepare the toner with a particle size in the range of 0.1 to 5 μm.

Methods for incorporating the above compound into the developer include a method of adding it inside the developer and a method of adding it externally. When internally added, the amount of these compounds used is usually 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polyester resin.

In addition, when externally added, 0.
01 to 10 parts by weight are preferred.

In addition, additives such as low molecular weight olefin polymers and finely powdered silica may be added externally or internally as constituent components of the developer of the present invention in order to improve fixing properties and fluidity.

As a method for producing toner particles, each of the above components is kneaded.
After kneading and cooling, the mixture may be crushed and classified.

On the other hand, the basic magnesium aluminum hydroxy carbonate hydrate to be mixed with the toner particles is represented by the following soft formula (■): MgpA 19(OH)r(co3), HmHz.

...(■) (In the formula, p, q, r and S represent integers satisfying 2p+3q=r+23, m represents any integer.) Among these, M g aA 1 z (OHL3COx・4HzO or Mg4. 5AZx(OH)+zCCh・3.5Hz
Compounds called hydrotalcites, such as O, are conveniently used.

Basic magnesium, aluminum, hydroxy,
Carbonate hydrate has the effect of improving the charging properties of the toner, and is particularly effective in promoting the rise of charging when starting or restarting use of the developer.

The amount used is 0.001 to 1 part by weight, preferably 0.01 part by weight, based on 100 parts by weight of the resin contained in the toner particles.
It is preferable to set it as 1 part by weight.

Further, the toner of the present invention can be applied not only to two-component developers but also to encapsulated toners, polymerized toners, and non-magnetic and magnetic one-component developers.

The average particle size of the toner is preferably 5 to 20 μm.

The carrier to be mixed with the toner of the present invention to form a developer is not particularly limited, but iron powder, ferrite powder, magnetite powder, magnetic resin carrier, etc. having an average particle size of 10 to 200 μm can be preferably used. In this case, it may be a coated carrier whose surface is coated with a resin or the like.

The mixing weight ratio of carrier and toner is 100:1 to 100:
20, more preferably 100:2 to 100:1O.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited in any way by the following Examples unless the gist thereof is exceeded.

In addition, in the following examples, the term "parts" simply means "parts by weight."

<Example 1> 100 parts of styrene resin (SBM
-600, manufactured by Sanyo Kasei ■) Quaternary ammonium salt charge control agent 2 parts Bontron P-51 (manufactured by Orient Chemical ■) was blended, kneaded, crushed, and classified to obtain a black toner with an average particle size of 11 μm.

To 100 parts of this black toner, 0.2 parts of fine silica powder (R-972 manufactured by Nippon Aerosil), 0.2 parts of hydrotalcite compound (Mg 6A lz (OH).4
0.3 part of fatty acid-treated fine powder of HzO) was externally added using a Henschel mixer.

4 parts of the obtained toner and 100 parts of a ferrite carrier coated with a silicone resin having an average particle size of 100 μm were mixed and stirred to prepare a developer.

Next, using this developer, a photocopying test was carried out on 100,000 sheets under high temperature/high humidity conditions of 40% to 5% to 90% using a copying machine having an organic photoconductor as a photoreceptor.

The replenishment toner used in the actual photography test had the same composition as the toner used for the developer described above.

As a result of the live-action test, even after 100,000 sheets were printed, there was no increase in fog, which is dirt on the white background of the copy.
The toner and developer had excellent durability even under harsh environments with high humidity.

<Example 2> The same procedure as in Example 1 was performed except that the amount of the fatty acid-treated fine powder of the hydrotalcite compound used in Example 1 was changed to 0.5 parts. A toner and a developer were obtained which showed no increase in fog, high uniformity and density in the black background area of copies, and excellent durability with no decrease in density.

<Example 3> The same procedure as Example 1 was carried out except that the amount of the fatty acid-treated fine powder of hydrotalcite a compound was changed to 0.1 part, and there was no increase in fog even after 100,000 sheets were photographed. Further, toners and developers with high uniformity and density in black background areas and excellent durability were obtained.

<Example 4> The same procedure as Example 1 was carried out except that 0.5 part of fine powder of hydrotalcite a compound which was not treated with fatty acids was used. There was no increase in fog even after a 100,000-sheet photo-photograph test, and no increase in density was observed. A toner and developer with excellent uniformity and durability with no decrease in density were obtained.

<Example 5> The same procedure as in Example 1 was carried out except that the amount of quaternary ammonium salt charge control agent used was 5 parts.
A durable toner and developer with no increase in fog, high uniformity of black background areas, and no decrease in density was obtained even after a 0-sheet photographing test.

<Example 6> The same procedure as Example 1 was performed except that polyester resin (manufactured by Mitsubishi Rayon ■) was used in place of the styrene resin. Even after a 100,000-sheet live-action test, there was no increase in fog and the black background area was uniform. A toner and developer with high properties and durability were obtained.

<Example 7> Polyester resin 100 parts (manufactured by Mitsubishi Rayon ■) Rhodamine B (xanthine dye - 3 parts C, I Solvent Red 49) Quaternary ammonium salt charge control agent 2 parts were blended,
The mixture was mixed, pulverized, and classified to obtain a magenta toner having an average particle size of 11 μm.

For 100 parts of this magenta toner, 12 parts of silica fine powder (R-972 manufactured by Nippon Aerosil ■) O and a hydrotalcite compound (M g , A 1 z (OH).4H
0.3 part of the fatty acid-treated fine powder of No. 20) was externally added using a Henschel mixer. 4 parts of the obtained toner and 100 parts of a ferrite carrier coated with a silicone resin having an average particle diameter of 100 μm were mixed and stirred to prepare a developer.

As in Example 1, the toner and developer were subjected to an actual photographing test, and even after testing 100,000 sheets, the toner and developer were free of fog and had high density uniformity.

<Example 8> The same procedure as in Example 3 was carried out except that 2 parts of nigrosine dye Bondron N-04 was used instead of the quaternary ammonium salt charge control agent Pontron P51.
Toners and developers with excellent durability were obtained, with no increase in fog even after actual copying, and with high uniformity and density in black background areas.

<Example 9> The same procedure as in Example 3 was carried out except that 2 parts of nigrosine dye Bontron NO9 was used instead of the quaternary ammonium salt charge control agent Pontron P-51.
Toners and developers with excellent durability were obtained, with no increase in fog even after actual copying, and with high uniformity and density in black background areas.

<Comparative Example 1> A toner and a developer were produced in the same manner as in Example 1 except that no hydrotalcite compound was used.
A live-action test was conducted.

As a result, there are problems such as abnormally high levels of stains, that is, fog on the white background, and the toner cannot be used in practice.

<Effects of the Invention> The positively chargeable toner for developing electrostatic images of the present invention has good charging performance, such as always showing moderate and stable chargeability, and is free from copy stains and images under high temperature and high humidity conditions or during continuous copying. It provides good images regardless of the usage conditions, such as little loss of density, and among others,
It is possible to effectively prevent toner scattering caused by poor charging of toner at the time of starting or resuming use of a developer, which has been a particular problem in the past, and provides great industrial benefits.

Issuing Person: Mitsubishi Kasei Corporation

Claims (1)

[Claims] (1) A positively chargeable toner for developing electrostatic images, characterized by containing toner particles containing at least a resin and a colorant, and basic magnesium aluminum hydroxy carbonate hydrate powder.