JPH02150860A - Positive chargeable toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To provide the toner which exhibits triboelectrostatic chargeability of a stable positive polarity, is excellent in environmental stability, is free from surface staining and toner splashing and forms the images of the high fidelity equiv. to the initial images even after continuous copying by incorporating a specific bisaminophenyl methane compd. into the toner. CONSTITUTION:The toner consisting of at least a binder resin and coloring agent contains the bisaminophenyl methane compd. expressed by the formula I. In the formula, R1 denotes 1 to 11C alkyl group, substd. or unsubstd. phenyl group, etc.; R2, R3 may be respectively the same or different and denote hydrogen, 1 to 14C alkyl group, etc.; R4, R5 may be respectively the same or different and denote hydrogen, alkyl group, etc. The toner which exhibits the triboelectrostatic chargeability of the stable positive polarity, is free from the surface staining and toner splashing, and forms the images equiv. to the initial images even after the continuous copying is obtd. in this way and the excellent environmental stability is obtd. as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrostatic image developing toner used in electrophotography, electrostatic printing, etc., and more particularly to a positively chargeable developing toner.

[Conventional technology]

Toner used as a developer in electrophotography, electrostatic printing, etc. is given a positive or negative charge depending on the polarity of the electrostatic image to be developed. As a method of applying electric charge, it is also possible to use the triboelectricity of the resin that is a component of the toner, but this method has the disadvantage that the toner's chargeability is not very large, so image fogging tends to occur and clear images cannot be obtained. There is. Therefore, as a method of imparting desired triboelectric charging properties, attempts have been made to add dyes, pigments, charge control agents, etc. that have charging properties.

Among such charge control agents, nigrosine oil-soluble dyes, azine dyes having an alkyl group, basic dyes, lakes of basic dyes, and the like are known as positive charge control agents. However, these dyes have complex structures, inconsistent properties, poor stability, and decomposition during hot kneading.
It is susceptible to decomposition or deterioration due to mechanical shock, friction, changes in temperature and humidity conditions, etc., and is susceptible to development that reduces charge controllability.

Furthermore, the charging properties of many materials change depending on the environment.

Furthermore, when a toner containing such a charge control agent is used for a long time, there are various problems such as filming on the photoreceptor due to poor charging.

[Problem to be solved by the invention]

The present invention overcomes the drawbacks of the above-mentioned prior art, exhibits stable triboelectrification of positive polarity, has excellent environmental stability, is free from scumming and toner scattering, and can be used with continuous copying machines to achieve fidelity equivalent to that of the initial image. An object of the present invention is to provide a positively chargeable toner for developing an electrostatic image, which gives an image with high image quality.

[Means to solve the problem]

As a result of repeated various experiments, the present inventors found that a toner containing a specific bisaminophenylmethane compound was suitable for the above purpose, and completed the present invention.

That is, according to the present invention, there is provided a positively chargeable toner for developing an electrostatic image, which is characterized in that the toner comprises at least a binder resin and a colorant, and contains a bisaminophenylmethane compound represented by the following general formula. Ru.

1(□ (wherein, R1, R2, R3, R4 and R5 each represent the following.

R□: Alkyl group having 1 to 11 carbon atoms, substituted or unsubstituted phenyl group, or heterocyclic % R2, R3: Each may be the same or different, hydrogen, alkyl having 1 to 4 carbon atoms R2 and R1 may be bonded to each other to form a nitrogen-containing heterocycle.

R4, R5: Each may be the same or different and represents hydrogen, an alkyl group, an alkoxy group, or a halogen. ) Specific examples of the compound represented by the above general formula used in the present invention include the following, but are of course not limited to these.

Table 1 The amount of the compound represented by the above general formula used in the present invention is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner manufacturing method including the dispersion method. Although not specifically limited, it is preferably used in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the binder resin.

If it is less than 0.1 part by weight, the toner will not be positively charged and is not practical. If the amount exceeds 20 parts by weight, the toner's chargeability is too high and the electrostatic attractive force with the carrier increases, resulting in a decrease in the fluidity of the developer and a decrease in image density.

The binder resin used in the present invention includes polystyrene,
Homopolymers of ethylene and its substituted products such as poly-P-chlorostyrene and polyvinyltoluene: styrene-p-chlorostyrene copolymers, styrene-propylene copolymers,
Styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer.

Styrene-butyl methacrylate copolymer, styrene-α
-Talol methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-
butadiene copolymer, styrene-isoprene copolymer,
Styrene-based copolymers of styrene-acrylonitrile-indene copolymer, styrene-maleic copolymer, styrene-maleic acid ester copolymer: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, Polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, Examples include paraffin wax, which can be used alone or in combination.

Furthermore, the binder resins particularly suitable for pressure fixing are limited to those shown below, which can be used alone or in combination.

Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polytetrafluoroethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5-30:95-70)
, olefin copolymers (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-
methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin), polyvinylpyrrolidone, methyl vinyl ether-anofomaleic acid copolymer, maleic acid Modified phenolic resin, phenol-modified terpene resin.

Colorants used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrolene dye, aniline blue, phthalocyanine blue, phthalocyanine green, Visor Yellow G, rhodamine 6G, lake, calco oil blue, chrome yellow, Any conventionally known dyes and pigments such as quinacridone, benzidine yellow, rose bengal, triallylmethane dyes monoazo, disazo, dyes and pigments can be used alone or in combination.

Further, when the toner of the present invention is used as a two-component developer, it is used in combination with a carrier powder.

As the vine carrier used in the present invention, all known carriers can be used, such as iron powder, ferrite powder,
Examples include magnetic powder such as nickel powder, glass beads, and those whose surfaces are treated with resin or the like.

Furthermore, the toner of the present invention can also be used as a magnetic toner containing a magnetic material. Magnetic materials contained in the magnetic toner of the present invention include Magnegi 1-. hematite 5
Metals such as iron oxide, iron, cobalt, and nickel such as ferrite, or these metals such as aluminum, cobalt,
Copper, button, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese.

Examples include alloys of metals such as selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 μm, and the amount to be included in the toner is about 20 to 200 parts per 100 parts by weight of the resin component. The amount of tZJL is particularly preferably 40 to 150 parts by weight per 100 parts by weight of the resin component.

Further, the toner of the present invention may contain additives as required. Examples of additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, or colloidal silica. , a fluidization agent such as aluminum oxide, an anti-caking agent, a conductivity agent such as carbon black or tin oxide, or a fixing aid such as low molecular weight polyethylene.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts represent parts by weight.

Example 1 Styrene-n-butyl methacrylate 100 parts Carbon black 10 parts Illustrative compound (Nα1) 2 parts A mixture of the above composition was thoroughly stirred and mixed in a Henschel mixer, and then mixed with a roll mill at a temperature of 130-140°C for about 3
After heating and melting for 0 minutes and cooling to room temperature, the resulting mixed material was crushed and classified to obtain a toner having a particle size of 5 to 10 μm.

1 coated with silicone resin for 2.5 parts of this toner.
A developer was obtained by mixing with 97.5 parts of a ferrite carrier having a mesh size of 00 to 250 in a ball mill.

Next, when the above developer was set in FT4060 manufactured by our company and one reversal development was performed, a good image was obtained, and the image did not change even after printing 200,000 images.

Furthermore, when the charge amount of the toner was measured using the blow-off method, the initial charge ffi amount was +14.8 μc/g, which was 2
The amount of charge on the toner after running 00,000 sheets was +15.
There was almost no difference from the initial value of 5 μcog. or.

Even in a high humidity environment of 35° C. and 90 meters RH and in a low humidity environment of 10 degrees centigrade (JL), images equivalent to normal humidity were obtained. Also, there was no toner filming on the photoreceptor.

Comparative Example 1 Instead of one exemplary compound (Nα1) in Example 1,
A developer was obtained in the same manner as in Example 1 except that nigrosine dye was used, and an image test was conducted. Initially, a clear image without fog was obtained, but after about 100,000 copies, the image became foggy and unclear, and toner filmin was observed on the surface of the photoreceptor. In addition, when an image test was conducted under high humidity at 35°C and 90% lIH, the image density was as low as 0.95.
An unclear image with fog was obtained. In addition, Example 1
When the charge amount was determined in the same manner as above, the initial charge amount was +19.8μe/g, but after 100,000 sheets, it became +9.
It had decreased to 2 μc/g.

Example 2 Polypropylene carbon black exemplified compound (Nα2) 1.5
A mixture having the above composition was mixed, pulverized, and classified to obtain a toner having a particle size of 5 to 20 tones. For 100 parts of this toner, 3 parts of silicon carbide (particle size 2-), 0 parts of hydrophobic colloidal silica
．． One part was sufficiently stirred and mixed using a speed kneader to prepare a toner.

When this toner was loaded into a developing device as shown in the drawings, continuous copying was performed, and an image test was conducted, good images were obtained. The image did not change even after 50,000 images were published.

To explain this developing method, as shown in the drawing,
The toner 6 contained in the toner tank 7 is stirred by the stirring blade 5.
The toner is forcibly brought to the sponge roller 4 and supplied to the sponge roller 4.

As the sponge roller rotates in the direction of the arrow, the toner taken into the sponge roller 4 is transported to the toner conveying member 2, where it is rubbed and electrostatically or physically adsorbed, and the toner conveying member 2 moves in the direction of the arrow. The elastic blade 3 rotates strongly to form a uniform thin layer of toner and is charged by friction. Thereafter, the toner is transported to the surface of the electrostatic latent image carrier 1 that is in contact with or in close proximity to the toner transport member 2.
The latent image is developed.

The electrostatic latent image is generated by applying a negative DC voltage of 800 V to the organic photoreceptor, and then exposing the organic photoreceptor to light to form a latent image, which is then developed. In addition, in order to measure the specific charge amount (Q/M) of the toner on the toner transport member, the toner on the toner transport member is sucked through a Faraday cage equipped with a filter layer on the exit side, and the toner is trapped inside the Faraday cage. When the Q/M was measured using an attraction charge amount measuring device for measuring the specific charge of the toner, it was confirmed that the toner was sufficiently charged as +9.5 μc/g.

Also, the amount of charge when running 50,000 sheets is (+9.0)
There was almost no difference between μc/g and the initial value.

Furthermore, image quality equivalent to that under normal humidity was obtained even under high humidity and low humidity conditions. Further, there was no toner filming on the photoreceptor.

Comparative Example 2 In Example 2, instead of the exemplary compound (Nn2),
An image test was conducted in the same manner as in Example 2, except that nigrosine dye was used. Initially, a clear image without fog was obtained, but after around 30,000 copies, the image became unclear with fog, and the photoreceptor surface Toner filming was observed. Furthermore, under high temperature and high humidity conditions, the image density was as low as 0.92. Further, when the charge amount was measured in the same manner as in Example 2, the initial charge amount was +10.7 μc/g, which was sufficient, but after running 50,000 sheets, it decreased to ÷2.9 μc/g.

Example 3 Styrene-〇-butyl methacrylate 100 parts Polyethylene 7 parts Carbon black 13 parts Exemplary compound (N
α6) 2 parts of the mixture with the above composition, cross-mixed, crushed and classified into 5-20μ
A toner having a particle size of ω was obtained. For 100 parts of this toner,
2.5 parts of silicon carbide (2,) and 0.4 parts of titanium oxide fine powder
The mixture was sufficiently stirred and mixed using a speed kneader to prepare a toner.

When this toner was subjected to an image test in the same manner as in Example 2, good images were obtained. The amount of charge is +9 at the start.
．． 0 μc/g, after 50,000 sheets there was almost no change to +8.0 μc/g, good images were obtained even under high humidity, and there was no filming on the surface of the photoreceptor.

Example 4 An image test was conducted in the same manner as in Example 1, except that the exemplified compound (Nα5) was used instead of the exemplified compound (Nα1). The amount of charge is +10.3 at the start.
There was almost no change in μc/g after 200,000 sheets, which was +9.4 μc/g. In addition, good images equivalent to those under normal humidity were obtained even under high humidity and low humidity. Further, there was no toner filming on the photoreceptor.

Examples 5 to 11 Toners were obtained in the same manner as in Example 2 using developer compositions shown in Table 1. Table 1 shows the image characteristics and charging properties of these toners.

〔Effect of the invention〕

Since the positively chargeable toner for electrostatic images of the present invention contains a bisaminophenylmethane compound represented by the above general formula as a positive charge control agent, in the case of a two-component system, there is In the case of a one-component system, the frictional charging between the toner and a charge imparting member such as a developing sleeve or blade can be maintained at a stable positive polarity.

Therefore, according to the positive '11IF11 toner for electrostatic images of the present invention, an image equivalent to the initial image can be obtained even after continuous copying without background smearing or toner scattering.

In addition, the positively chargeable toner for electrostatic images according to the present invention does not change its performance such as triboelectricity even if the environment such as mechanical shock, friction or temperature/humidity conditions changes, so it can be used in various applications. It provides stable, high-quality images even under environmental conditions, and does not cause filming on the photoreceptor even after long periods of use.

[Brief explanation of the drawing]

The drawings are explanatory diagrams of a developing method using the toner of the present invention.

Claims (1)

[Claims] (1) A positively chargeable toner for developing electrostatic images, which comprises at least a binder resin and a colorant, and contains a bisaminophenylmethane compound represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1, R_2, R_3, R_4 and R_5 each represent the following. R_1: Alkyl group having 1 to 11 carbon atoms, substituted or unsubstituted phenyl group, or a heterocyclic group. R_2, R_3: each may be the same or different and represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloroalkyl group, or a substituted or unsubstituted aralkyl group. , R_2 and R_3 may be bonded to each other to form a nitrogen-containing heterocycle. R_4, R_5: Each may be the same or different and represents hydrogen, an alkyl group, an alkoxy group, or a halogen.)