JPH0727278B2 - Non-magnetic one-component developer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) A non-magnetic one-component developer composition for visualizing an electric latent image or electric signal in electrophotography, electrostatic recording, etc., particularly,
The present invention relates to a non-magnetic one-component developer composition having excellent negative charging property, developing property and transfer property.

(Prior Art) Various methods are known as a method for imparting an electric charge to a developer (toner), such as friction, a contact charging method, an ion irradiation method, an electrostatic induction method utilizing conductivity, and a charge injection method. However,
Friction is the most easy to use and widely used
Alternatively, it is a contact charging method.

As a developer used in this case, in order to give an electric charge to the toner, in addition to a two-component developer in which carrier particles that are charged in a polarity opposite to that of the toner are mixed with the toner, friction charging of the toner with a charging blade or a charging roll is used. Alternatively, a one-component developer that uses triboelectric charging between toners is known.

When charging the toner by such contact charging and friction charging,
It is necessary to add an electron-donating substance or an electron-withdrawing substance to the toner side or the charge-giving material side such as a carrier or a blade to control the charging property. Although triboelectrification development is complicated and its mechanism is not always clear, generally, an electron-donating substance is positively charged and an electron-withdrawing substance is negatively charged.

Conventionally, in order to control the charging of the toner, (i) a dye or pigment in the toner or on the surface of toner particles,
Surfactant are mixed adding inorganic powder or the like, a resin-like material having -COOH, -CN, halogen -Cl etc., -NO _2, a functional group such as -NH ₂ as (ii) a binder resin, The means is taken. Further, it is known that the acid anhydride itself has charge controllability or rheological property controllability to some extent, and comparison of acid values using an acid anhydride such as maleic anhydride as a component of the binder resin of the toner. A low binder resin has been conventionally known.

(Problems to be Solved by the Invention) However, these conventional techniques have not succeeded in controlling the temporal stability of the toner charging property and the environmental stability, and have not reached a satisfactory level.

Further, sufficient colorless or light-colored charge control agents usable for colors have not been known.

Therefore, an object of the present invention is to provide a non-magnetic one-component developer composition in which the toner charge rises quickly and to control the toner charge amount and to provide a sharp charge distribution in the non-magnetic one-component developer composition. To provide a non-magnetic one-component developer composition which is excellent in environmental stability of toner charging and stability over time, and therefore, developability and transferability are improved to ensure always good image quality. And a non-magnetic one-component developer composition using a colorless or light-colored charge control agent capable of acting on the formation of a color image. is there.

(Means and Actions for Solving Problems) As a result of earnest research, the present inventors have found that an acid anhydride-containing styrene-based copolymer having an extremely high acid value was added to the toner, which was significantly different from the prior art. It was confirmed for the first time that different effects were produced, and the present invention was completed.

That is, the above-mentioned object of the present invention is, in a non-magnetic one-component developer composition containing a colorant and a binder resin as main components, an acid anhydride group as a polar functional group or an acid group formed by partial esterification thereof. And an acid value of more than 100 and having at least styrene as a monomer unit (hereinafter referred to as a styrene-based copolymer).

Examples of the styrene-based copolymer having an acid anhydride group used in the present invention include acrylic acid anhydride, methacrylic acid anhydride, acrylic acid propionic acid anhydride, acrylic acid methacrylic acid anhydride, itaconic acid anhydride, and anhydrous. Examples of the copolymer include maleic acid, citraconic anhydride, dimethyl maleic anhydride and the like as monomer components.

These styrene-based copolymers are copolymers containing the above-mentioned acid anhydride group-containing monomer and at least styrene as a monomer, but in order to ensure compatibility with other binder resins of the toner, etc. It may be a copolymer with the monomer component of, for example, acrylate.

Of these, a styrene-based copolymer containing maleic anhydride as a monomer component is industrially manufactured at low cost and is therefore easily available.

The acid anhydride is decomposed in the presence of water, for example, acrylic acid in the case of acrylic acid anhydride is changed to maleic acid in the case of maleic anhydride, but in the present invention, the acid anhydride present in the polymer chain is used. The group may be decomposed in the presence of water to be converted into, for example, two adjacent carboxylic acid groups.

In the present invention, the monomer component forming the acid anhydride group may be one kind or two or more kinds.

In the styrene-based copolymer having these acid anhydride groups, the acid anhydride groups may be partially esterified. The partial esterification is carried out by an esterification reaction with alcohols, for example, the reaction is carried out according to the following formula.

(In the formula Is a polymer chain and R represents an alcohol residue. The styrene-based copolymer having an acid anhydride group or an acid group formed by partial esterification thereof in the present invention is characterized by having an acid value of more than 100. In the present invention, the reason why using an acid value of more than 100 causes a large difference in action and effect compared to the conventional one, the reason is not necessarily clear, but in any case, such a high acid By adding a small amount of a valent polymer, a very rapid rise of charging, environmental stability, and narrow charge distribution are exhibited.

The styrene copolymer in the invention has an acid value of about 50 or less in the entire toner binder resin, preferably about 30 to about 0.
It is recommended to use it in a diluted state so that it will be about 5.

As the other binder resin used in the present invention, any one of styrene type, acrylic type, olefin type, polyester, epoxy, polycarbonate, polyamide, polyurethane, silicone type, fluorine type, petroleum resin and the like can be used.

In the non-magnetic one-component developer composition of the present invention, known compounds can be used as the colorant and other components. If it falls, dyes and pigments such as carbon black, cyan, magenta, and yellow colors can be used as the colorant, and a conductivity adjuster, an inorganic substance such as a metal oxide, a reinforcing filler, an antioxidant, etc. may be contained. be able to. A known charge control agent may be used in combination.

An external additive may be used in the non-magnetic one-component type developing composition of the present invention. As the external additive, conventionally known ones such as silica, carbon, alumina, titanium oxide, zinc oxide, resin fine powder and tin oxide can be used.

In the non-magnetic one-component developer composition of the present invention, the toner can be manufactured by any known method such as a kneading and pulverizing method, a spray dry method, and a direct polymerization method.

The toner particle size is preferably such that the average particle size d50 measured by the Coulter counter method is in the range of 1 to 20 μm, and more preferably in the range of 5 to 15 μm.

(Example) Next, although an Example demonstrates this invention, this invention is not limited by these.

Reference Example 1 ○ Styrene / maleic anhydride copolymer (acid value about 480) 4
Parts styrene / butyl acrylate copolymer 86 parts carbon black 10 parts The above components were kneaded and pulverized by a conventional method to obtain a toner having an average particle diameter of 12 μm. The obtained toner was mixed with an iron powder carrier having a particle size of about 100 μm so that the toner concentration would be about 3%. The blow-off tribo method was used to measure the amount of blow-off charge on the obtained developer.
RH80%), normal temperature / humidity, low temperature / low humidity (10 ° C, RH20%), the charge amount was in the range of about −15 μc / g to −20 μc / g and was extremely stable. Further, when measured by a charge spectrograph method, the charge distribution was sharp, no reverse polarity toner was observed, and the rise of charging was quick.

To this toner, 0.7% by weight of hydrophobic silica fine powder and 0.5% by weight of fatty acid metal salt were added and mixed, and further the particle size was about 80 μm.
Was mixed with a ferrite carrier of No. 1 to prepare a developer, and a copying machine (Fuji Xerox Co., Ltd., FX-2830 ^R ) was used to perform a continuous copying test of 50,000 sheets. As a result, a copy with extremely good image quality was obtained. .

Reference Example 2 ○ Styrene / maleic anhydride copolymer (acid value about 270) 6
Part: styrene / n-butyl acrylate copolymer 30 parts: crosslinked styrene / butadiene copolymer 50 parts: polypropylene wax 4 parts carbon black 10 parts as a toner in the same manner as in Reference Example 1, d50 = 12 μm
m toner was obtained. When the charge amount of this toner was evaluated in the same manner as in Reference Example 1, the blow-off charge amount was about −14 μc / g in all environments of normal temperature and normal humidity, low temperature and low humidity, and high temperature and high humidity.
To about -18 μc / g, it was extremely stable, and the rise of charging was quick. The charge distribution was also sharp, and no reverse polarity toner was seen.

To this toner, 0.8% by weight of hydrophobic silica fine powder and 0.7% by weight of methyl methacrylate copolymer fine powder were added,
After mixing and further mixing with a ferrite carrier with a particle size of about 80 μm to prepare a developer, a continuous copying test of 50,000 sheets was performed with a copying machine (FX-2830 ^R ), and a copy with extremely good image quality was obtained. It was

Example 1 0.8 wt% of hydrophobic silica fine powder and 0.3 wt% of methylmethacrylate resin powder were added to and mixed with the toner of Reference Example 2 to prepare a one-component developer. Using this developer, a copying machine equipped with a one-component developing device shown in the drawing (remodeled FX-2830
^{In R} ), a continuous copying test of 10,000 sheets was performed, and an extremely good image was obtained.

In the one-component developing machine shown in the drawings, numeral 1 is a charging / metalling blade which is made of modified silicone rubber and plays a role of imparting an electric charge to the toner by frictional charging. 2 is a developing roll, which is a hard resin roll having an electric resistivity of the surface layer of about 10 ¹⁰ Ω · cm. The charged toner is held in a roll shape and is conveyed to the latent image portion for development. 3 is an auxiliary roll, which is a rubber-like roll having an electric resistivity of about 10 ³ Ω · cm. It serves to even out the charging history of the toner and to mechanically supply the toner in the form of a developing roll. In addition, 4 is a toner. It is also shown that a thin layer of toner is formed.

Example 2 ○ Styrene / maleic anhydride copolymer (acid value about 270) 5
Part ○ Styrene / butyl acrylate copolymer 91 parts ○ Vezidine yellow pigment 4 parts was made into a toner in the same manner as in Reference Example 1, and d50 = 12 μm.
Yellow toner was obtained. When the toner charge amount was evaluated in the same manner as in Reference Example 1, the blow-off charge amount was about −15 in all environments of normal temperature and normal humidity, low temperature and low humidity, and high temperature and high humidity.
The range was from μc / g to about −21 μc / g, which was extremely stable, and the rise of charging was quick. The charge distribution was also sharp, and no reverse polarity toner was seen.

0.7 wt% of hydrophobic silica fine powder and 0.4 wt% of titanium oxide fine powder were added to and mixed with this toner to prepare a one-component developer. This toner was subjected to a continuous copying test of 5,000 sheets with a copying machine (modified FX-2830 ^R ) equipped with the developing machine of Example 1, and a good yellow image with extremely good color development was obtained.

Reference Example 3 ○ Partially esterified styrene / maleic anhydride copolymer (acid value about 175) 10 parts ○ Styrene / butyl acrylate copolymer 80 parts ○ Carbon black 10 parts Average particle size as in Reference Example 1 12 μm of toner was obtained. The obtained toner was mixed with an iron powder carrier having a particle size of about 100 μm so that the toner concentration would be about 3%. About the obtained developer, when the blow-off tribo method was used to measure the blow-off charge amount, the charge amount was about −15 μc / g to −18 μc / g in all environments of high temperature and high humidity, normal temperature and normal humidity, and low temperature and low humidity. The range was extremely stable. Also,
When measured by a charge spectrograph method, the charge distribution was sharp, no reverse characteristic toner was observed, and the rise of charging was quick.

To this toner, 0.7% by weight of hydrophobic silica fine powder and 0.5% by weight of fatty acid metal salt were added and mixed, and a particle size of about 80μ
m was mixed with a ferrite carrier to prepare a developer, and a continuous copying test of 50,000 sheets was carried out with a copying machine (FX-2830 ^R ). As a result, a copy having an extremely good image quality was obtained.

Reference Example 4 ○ Partially esterified styrene / maleic anhydride copolymer (acid value: about 105) 10 parts ○ Styrene / n-butyl acrylate copolymer 30 parts ○ Crosslinked styrene / butadiene copolymer 44 parts ○ Polypropylene wax 4 parts ○ 10 parts of carbon black was converted to toner in the same manner as in Reference Example 1, and d50 = 12μ.
m toner was obtained. When the toner charge amount was evaluated in the same manner as in Reference Example 1, the blow-off charge amount was about −13 μc / g in all environments of normal temperature and normal humidity, low temperature and low humidity, and high temperature and high humidity.
To about −16 μc / g, it was extremely stable, and the rise of charging was quick. The charge distribution was also sharp, and no reverse polarity toner was seen.

To this toner, 0.8% by weight of hydrophobic silica fine powder and 0.7% by weight of methyl methacrylate copolymer fine powder were added,
After mixing and further mixing with a ferrite carrier with a particle diameter of about 80 μm to prepare a developer, a continuous copying test of 50,000 sheets was performed with a copying machine (FX-2830 ^R ), and a copy with extremely good image quality was obtained. It was

Example 3 To the toner of Reference Example 4, 1.2% by weight of hydrophobic silica fine powder and 0.3% by weight of methylmethacrylate resin fine powder were added and mixed to prepare a one-component developer. Using this developer, a copying machine equipped with a one-component developing device shown in the drawing (remodeled FX-2830
^{In R} ), a continuous copying test of 10,000 sheets was performed, and an extremely good image was obtained.

Example 4 ○ Partially esterified styrene / maleic anhydride copolymer (acid value of about 175) 5 parts ○ Styrene / butyl acrylate copolymer 91 parts ○ Benzidine yellow pigment 4 parts was made into a toner in the same manner as in Reference Example 3. d50 = 12μm
Yellow toner was obtained. When the toner charge amount was evaluated in the same manner as in Reference Example 1, the blow-off charge amount was about −16 in all environments of normal temperature and normal humidity, low temperature and low humidity, and high temperature and high humidity.
The range was from μc / g to about −20 μc / g, which was extremely stable, and the rise of charging was quick. The charge distribution was also sharp, and no reverse polarity toner was seen.

0.7 wt% of hydrophobic silica fine powder and 0.4 wt% of titanium oxide fine powder were added to and mixed with this toner to prepare a one-component developer. This toner was subjected to a continuous copying test of 5,000 sheets with a copying machine (modified FX-2830 ^R ) equipped with the developing machine of Example 1, and a good yellow image with extremely good color development was obtained.

Comparative Example styrene / butyl acrylate / maleic anhydride copolymer (acid value about 15) 90 parts carbon black 10 parts The above components were kneaded and pulverized to obtain a toner having an average particle diameter of about 12 μm. The above toner was mixed with an iron powder carrier having a particle size of about 100 μm so that the toner concentration would be about 3%. When the blow-off charge amount was measured in the same manner as in Reference Example 1, it was about −12 μc / g at room temperature and normal humidity. The amount of polar toner was large. Also, in the high temperature and high humidity state, the blow-off charge amount is about −6 μm.
It became c / g, the amount of reverse polarity toner further increased, and the environmental stability of charging was poor.

(Effect of the invention) The non-magnetic one-component developer composition of the present invention has an acid anhydride group or an acid group formed by partial esterification thereof, has an acid value of more than 100, and contains at least styrene as a monomer. Since it contains a copolymer as a body unit, it has negative chargeability, developability,
Excellent transferability.

That is, the non-magnetic one-component developer composition of the present invention has a rapid rise in toner charging, can control the toner charge amount, has a sharp charge distribution, and has excellent environmental stability of toner charging, It has excellent stability. Therefore, the developability and transferability of the conventional developer composition are improved, and a copy having good image quality can always be obtained. Furthermore, since the styrene-based copolymer is colorless or light-colored, the non-magnetic one-component developer composition of the present invention is effective for forming a color image.

[Brief description of drawings]

The drawings are cross-sectional views of the essential parts of a one-component developing machine for using the non-magnetic one-component developer composition of the present invention. 1 ... Charging / metering blade, 2 ... Developing roll,
3 ... Auxiliary roll, 4 ... Toner.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Susumu Saito 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Takematsu Office (56) References JP-A-60-108861 (JP, A) JP-A-59- 139053 (JP, A) JP 61-99152 (JP, A) JP 55-134861 (JP, A) JP 60-254157 (JP, A) JP 61-138259 (JP, A)

Claims (1)

[Claims] 1. A non-magnetic one-component developer composition comprising a colorant and a binder resin as main components, which has an acid anhydride group or an acid group formed by partial esterification thereof as a polar functional group. A non-magnetic one-component developer composition having an acid value of more than 100 and containing at least a copolymer containing styrene as a monomer unit.