JPS63257765A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain the image having the quality equivalent in that of an initial image, even after continuously copying by using a specified compd. as an electrostatic charge controller. CONSTITUTION:The compd. shown by the formula is incorporated in the charge controller of the titled toner. In the formula, R1 and R2 are each 1-10C alkyl group and may be the same or the different with each other, X is hydrogen atom, 1-10C alkyl, alkoxy or aryl group which is substd. or unsubstd. aralkyl or amino group. Thus, the frictional electrification is stable, and the distribution of the frictional electrification can be made to sharp and uniform. Accordingly, the clear color toner is obtd., and the greasing and the scattering of the toner do not occur, and the image having the high faithfulness equivalent in that of the initial image is obtd., even at the time of continuously using.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing electrostatic images used in electrophotography, electrostatic printing, etc., and particularly relates to a positively charging toner for developing.

As disclosed in JP-A No. 61-147261, methods for developing electrostatic images using toner have been broadly divided into so-called two-component developers in which toner and carrier are mixed. There is a method using a one-component developer, and a method using a one-component developer in which the toner is used alone without being mixed with a carrier.

In the method described above, toner and carrier are charged to different polarities by stirring and friction, and an electrostatic charge image having opposite polarity is visualized by the charged toner. Depending on the type of
Examples include the magnetic brush method using an iron powder carrier, the cascade method using a bead carrier, and the fur brush method.

The latter one-component development method includes a powder cloud method in which toner particles are sprayed, and a contact development method (also referred to as touchdown development) in which toner particles are brought into direct contact with an electrostatic latent image surface for development.

There is an induction development method in which a magnetic conductive toner is brought into contact with an electrostatic latent image surface.

Toners applicable to these various developing methods include:
A fine powder in which a colorant such as carbon black is dispersed in a binder resin made of natural or synthetic resin is used.For example, a colorant is dispersed in a binder resin such as polystyrene. Finely pulverized particles of about 1 to 30 microns are used as toner. Further, a toner containing these components further contains a magnetic material such as magnetite is used as a magnetic toner.

As mentioned above, toners used in various developing methods are:
Depending on the polarity of the electrostatic charge image to be developed, a positive or negative charge is retained, and in order to cause the toner to retain a charge, it is also possible to utilize the triboelectricity of the resin that is a component of the toner. In this method, since the toner has a low chargeability, the image obtained by development tends to be foggy and unclear. Therefore, in order to impart desired triboelectric chargeability to the toner, dyes, pigments, or charge control agents that impart chargeability are added to the toner.

JP 61-143771 discloses the use of phosphine as a charge control agent.

Conventionally, positive charge control agents include nigrosine-based oil-soluble dyes, azine dyes with alkyl groups, basic dyes, and basic dye lakes, but these dyes have complex structures and constant properties. It is easy to decompose or change in quality due to decomposition during thermal kneading, mechanical impact, friction, changes in temperature and humidity conditions, etc., and it is easy to cause development that reduces charge controllability, or it is charged due to the environment. Many of them change gender.

Furthermore, when a toner containing the conventional charge control agent is used for a long time, filming may occur on the photoreceptor due to poor charging.

The object of the present invention is to provide a solution between toner particles, or between a toner and a carrier, or between a toner and a carrier in the case of component development.

It is an object of the present invention to provide a toner that is stable in frictional charging with a charge imparting member such as a developing sleeve or blade, has a sharp and uniform triboelectric charge distribution, and can be controlled to a charge amount suitable for the developing system used. , yet another purpose is to provide vivid color toners.

Another purpose is to eliminate background smudges and toner scattering.

It is an object of the present invention to provide a toner that can provide images with high fidelity equivalent to the initial image even during continuous use.

1-1 As a result of intensive studies, the present inventors have obtained a positively chargeable toner for developing electrostatic latent images that improves the above-mentioned conventional drawbacks by containing a compound represented by the following structural formula. was completed.

General formula (where R1 and R2 are alkyl groups having 1 to 10 carbon atoms,
These may be the same or different at the same time.
(also represents hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a substituted or unsubstituted aryl group, an aralkyl group, or an amino group) Representative of the compound of the above general formula used as a charge control agent in the present invention Specific examples include the following, all of which are white or pale yellow.

(Hereinafter in the margin) (Hereinafter in the margin) The amount of the compound used as a charge control agent in the present invention is determined based on the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method in toner production. Although it is determined by the method and is not uniquely limited, it is preferably 0.1 parts by weight per 100 parts by weight of the binder resin.
It is used in a range of 20 parts by weight. If it is less than 0.1 part by weight, the toner will not be positively charged and is not practical, and if it exceeds 20 parts by weight, the toner will have too much chargeability and the electrostatic attraction force with the carrier will increase, making it difficult to develop. This leads to a decrease in the fluidity of the agent and a decrease in image density.

The binder resin used in the present invention includes polystyrene,
Monopolymers of styrene and its substituted products such as polyp-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 Coalescence, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-methyl chloromethacrylate 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-acrylonitrile-indene copolymer, styrene- Styrenic copolymers such as maleic acid copolymers and styrene-maleic acid ester copolymers; 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.

Examples include aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc., which can be used alone or in combination.

In particular, the following binder resins suitable for pressure fixing may 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-a, glycated 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-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin.

Colorants used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, lake,
Calco oil blue, chrome yellow, quinacridone,
Any conventionally known dyes and pigments such as benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, 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.

All known carriers can be used in the present invention, such as iron powder.

Examples include magnetic powders such as ferrite powder and nickel powder, glass beads, and those whose back surfaces are treated with resin or the like.

Furthermore, the toner of the present invention further contains a magnetic material and can be used as a magnetic toner. Examples of the magnetic material contained in the magnetic toner of the present invention include magnetite, hematite,
Iron oxides such as ferrite, metal acids such as iron, cobalt, nickel, or these metals such as aluminum, cobalt, copper, lead, 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 by weight per 100 parts by weight of the resin component, particularly preferably 100 parts by weight of the resin component. 40 to 150 parts by weight.

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, etc. Fluidization agents such as aluminum oxide, anti-caking agents, or conductivity agents such as carbon black and tin oxide,
Alternatively, there are fixing aids such as low molecular weight polyethylene.

Hereinafter, the present invention will be explained in more detail with reference to the following examples, but the present invention is not limited thereto. All parts are by weight.

Example 1 Styrene-n-butyl methacrylate 100 parts Polypropylene 5 parts C,1, Pigment Blue 15 5 parts Exemplary compound (1)
5 parts The mixture having the above composition was sufficiently stirred and mixed in a Henschel mixer, and then mixed with a roll mill at a temperature of 130 to 140°C for about 3 parts.
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded product was crushed and classified to obtain a toner having a particle size of 5 to 10 μm.

For 2.5 parts of this toner, ferrite carrier of 100 to 250 mesh coated with silicone resin is used.
A developer was obtained by mixing the two parts in a ball mill.

Next, the above developer was set in our layer FT4060 and reversal development was performed, and a good image was obtained, which remained unchanged even after printing 200,000 copies.

In addition, when the amount of charge on the toner was measured using the blow-off method, the amount of charge at the initial stage was +16.1μc/g, and the amount of charge on the toner after running 200,000 sheets was +15.7μc/g.
/g, there was almost no difference from the initial value. Also 35℃90%
Images equivalent to those at room temperature were obtained even under a high temperature environment of RH and a low humidity of 10'C15%RH.

Further, there was no toner filming on the photoreceptor.

Comparative Example 1 A developer was obtained in the same manner as in Example 1, except that nigrosine dye (Nigrosine EX manufactured by Orient Chemical Industry Co., Ltd.) was used instead of Exemplified Compound (1) in Example 1, and a one-image test was conducted. The initial image was clear with no fog, but
After about 100,000 copies, images became foggy and unclear, and toner filming was observed on the surface of the photoreceptor. Also, 3
When we conducted an image test under high humidity at 5°C and 90% RH,
The image density was as low as 0.95, and an unclear image with fog was obtained.

Further, when the charge amount was measured in the same manner as in Example 1, the initial charge amount was +19.8 μe/g, but after 100,000 sheets, it was found to have decreased to +9.2 μc/g.

Example 2 Polypropylene 5 parts C, 1,
Pigment Red 57 5 parts C,1, Pigment Red 48 3 parts Exemplary Compound (2)
Three parts of the mixture having the above composition were mixed, pulverized, and classified to obtain a toner having a particle size of 5 to 20 μm. To 100 parts of this toner, 3 parts of silicon carbide (particle size: 2 μm) and 0.1 part of hydrophobic colloidal silica were sufficiently stirred and mixed using a speed kneader to prepare a toner.

This toner is loaded into a developing device as shown in Figure 1,
When continuous copying was performed and a one-image test was performed, a good image was obtained. The image remained unchanged even after printing 50,000 images.

To explain this developing method, as shown in the drawing, the toner 6 contained in the toner tank 7 is forcibly brought to the sponge roller 4 by the stirring blade 5, and the toner is supplied to the sponge roller 4. Then, as the sponge roller rotates in the direction of the arrow, the toner taken into the sponge roller 4 is carried to the toner conveying member 2, where it is rubbed and electrostatically or physically attracted.

The toner conveying member 2 rotates strongly in the direction of the arrow, and a uniform thin layer of toner is formed by the elastic blade 3, 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, and the latent image is developed.

The electrostatic latent image is created by charging the organic photoreceptor with a negative DC voltage of 800V, exposing it to light, forming a latent image, and developing it.

In addition, in order to measure the specific charge amount (Q/M) of the toner on the toner conveying member, the toner on the toner conveying member is sucked through a Faraday cage equipped with a filter layer on the exit side, and is trapped in the Faraday cage. When Q/M was measured using a suction method specific charge measurement device that measures the specific charge of the toner, it was +11. It was confirmed that a sufficient charge of Oμc/g was achieved.

Also, the amount of charge during running of 50,000 sheets is +10.5 μc.
/g, there was almost no difference from the initial value.

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

Example 3 Epoxy resin 100 parts Polyethylene 10 parts C.1, Pigment Blue 15 2 parts C.1, Pigment Yellow 17 5 parts Exemplary compound (5) 2 parts A raw material mixture having the above composition was melted and mixed in the same manner as in Example 1. ,
The mixture was crushed and classified to obtain a green toner having a particle size of 5 to 20 μm.

Five parts of this toner were mixed with 100 parts of iron powder carrier of 100 to 200 mesh to obtain a developer.

Next, this developer was applied to our copying machine FT-
4060 and performed an image test, similar to Example 1, a good image with a bright green color was obtained, and the image did not change even after printing 200,000 images under high humidity or low humidity. However, I was able to obtain images that were almost the same as those at room temperature. Additionally, there was also a slight variation in the charge of the toner.

Charge amount: initial +17.2μc/g, after 200,000 sheets +15.
8 μc/g Comparative Example 2 A toner was prepared in the same manner as in Example 2, except that a quaternary ammonium salt (benzylmethyl-hexadecyl ammonium chloride) was used instead of Exemplified Compound (2) in Example 2, and an image test was conducted. Ta. In the initial stage, a clear image without fog was obtained, but from around the 10,000th image, fog started to appear and the image became unclear. In addition, when an image test was conducted under high humidity at 35°C and 90% RH, the image density was 0.86.
This was low, and fogging also occurred.

Further, when the amount of charge was measured in the same manner as in Example 2, it was found to be +8.2 μc/g initially, but after 50,000 sheets, it was +2.
It had decreased to lμc/g.

Example 4 Unsaturated polyester resin 100 parts Polypropylene 5 parts Carbon black 10 parts Exemplary compound (6) 3 parts A raw material mixture having the above composition was melted and mixed in the same manner as in Example 2,
The mixture was crushed and classified to obtain a black toner having a particle size of 5 to 20 μm.

For 100 parts of this toner, silicon hydrocarbon (particle size 2μ+*
) and 0.1 part of hydrophobic colloidal silica were sufficiently stirred and mixed using a speed kneader in the same manner as in Example 2 to prepare a toner.

When this donor was developed in the same manner as in Example 2 using the same developing device and an image test was conducted, a clear and good image was obtained, and the image did not change even after 50,000 images were printed.

Charge amount: initial +8.2μe/g, +7.5μ after 50,000 sheets
c/g Examples 5 to 8 Toners were obtained in the same manner as in Example 1 using the developer composition shown in the following table. The image properties and charging properties of these toners are also summarized in the table.

(The following is a blank space) As stated above, by using the specific compound of the present invention as a charge control agent, images with the same quality as the initial image can be obtained even after continuous copying, and positive polarity A toner exhibiting stable triboelectric charging properties can be obtained. Furthermore, a toner with good dispersibility in the binder resin and excellent environmental stability can be obtained, and clear color images can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a developing device used in an example of the present invention. 1... Electrostatic latent image carrier 2... Toner conveying member 3.
...Elastic blade 4...Sponge roller 5...
- Stirring blade 6... Toner 7... Toner tank

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, R_1 and R_2 are alkyl groups having 1 to 10 carbon atoms, and these may be the same or different at the same time. (X represents hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a substituted or unsubstituted aryl group, an aralkyl group, or an amino group) as a charge control agent. Characteristic toner for developing electrostatic images.