JP3186512B2 - Electrophotographic decolorizable toner, developer using the toner, and decoloring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner capable of erasing a formed image and erasing the formed image by immersion in a treatment water containing chlorine or exposure to a gas containing chlorine. About the method.

[0002]

2. Description of the Related Art In recent years, reuse of paper as a recording material of an electrophotographic toner has been proposed and studied from the viewpoint of resource saving and forest protection. One of them is the use of a decolorable toner that can be decolored by irradiating near infrared rays.
This uses a relatively heat-resistant and light-resistant cyanine dye or the like as a coloring agent. There was a problem that it was easy to occur.

[0003]

SUMMARY OF THE INVENTION The present inventor has proposed an electrophotographic toner and an electrophotographic toner which are hardly subjected to decoloration, fading, and discoloration under production conditions and storage conditions after production, and which can easily decolor a formed image. As a result of studying the decoloring method, the present invention has been achieved.

[0004]

Means for Solving the Problems The first invention is directed to an electrophotographic toner comprising an inorganic pigment, spinel green or an organic pigment, a pyrrolopyrrole-based coloring agent, a binder resin and an additive. A decolorizable electrophotographic toner characterized in that the formed product is decolorized by chlorine-containing water or chlorine-containing gas,
A second invention is an electrophotographic developer using such an electrophotographic toner and a carrier.
By a method of erasing an image formed using an electrophotographic toner comprising a spinel green as an inorganic pigment or a pyrrolopyrrole-based colorant as an organic pigment, a binder resin and an additive by chlorine-containing water or a chlorine-containing gas. is there.

[0005] As the binder resin in the present invention,
Styrene resins such as polystyrene and copolymers of styrene and other vinyl monomers are mainly used. Other vinyl monomers include unsaturated monoolefins such as ethylene, propylene and isobutylene; vinyl esters such as vinyl acetate; vinyl ethyl ketone and vinyl ketone such as vinyl hexyl ketone; N-vinyl pyrrole;
N-vinyl compounds such as vinylpyrrolidone; acrylonitrile; methacrylonitrile; acrylamide; methacrylamide and mixtures thereof are used. As the resin for toner, polyethylene, polypropylene, vinyl ester resin, rosin-modified phenol resin, epoxy resin, polyester resin and the like can be used in addition to the above-mentioned styrene resin.

In the present invention, it is important to use a colorant having relatively excellent heat resistance and light resistance. As the inorganic pigment, spiryl green can be used, and as the organic pigment, pyrrolo pyrol can be used.

[0007] The additives used in the present invention include silica fine particles, titanium dioxide fine particles, alumina fine particles, magnesium fluoride fine particles, boron carbide fine particles, titanium carbide fine particles, zirconium carbide fine particles, boron nitride fine particles, and nitrides as fluidizing agents. Examples include titanium fine particles, zirconium nitride fine particles, magnetite fine particles, molybdenum disulfide fine particles, aluminum stearate fine particles, magnesium stearate fine particles, and zinc stearate fine particles.

The essential components of the present invention are the above-mentioned components,
If necessary, a dispersing agent, a charge controlling agent, a wax as an anti-offset agent, an ultraviolet absorber, an antioxidant and the like can be appropriately compounded.

Electrophotographic developers are classified into a dry type and a wet type. The dry type is further classified into a one-component type and a two-component type. In the case of a one-component system, a colorant, a binder resin, a magnetic powder or a non-magnetic powder, a charge control agent, etc. are kneaded while heating, and a toner manufactured by a general method of pulverization and classification is used as a developer. I do. In the case of a two-component system, a toner obtained by kneading, pulverizing and classifying a colorant, a binder resin, a charge control agent and the like while heating, a carrier composed of magnetic particles such as iron powder and ferrite, and a magnetic particle surface. And a mixture with carrier particles such as a dispersion type carrier obtained by dispersing a magnetic fine powder in a binder resin. In the case of a wet method, a colorant, a binder resin, a charge control agent, and the like are added to a dispersion medium and dispersed by a disperser. The toner for electrophotography of the present invention is used for both dry and wet toners.

Images formed using the electrophotographic toner of the present invention are decolorized by the bleaching action of chlorine of the colorant used in the electrophotographic toner with chlorine water or chlorine gas. It is considered something. Chlorine water or chlorine gas used for decoloring has a chlorine concentration of 500 pp
m or more, more preferably 200
0 ± 100 ppm.

[0011]

The present invention will be described below with reference to examples. Examples 1 to 14, Comparative Examples 1 and 2 100 parts by weight of styrene-acrylic resin (manufactured by Goodyear, CPR-7022) and polypropylene wax (manufactured by Mitsui Petrochemical Industries, NP50)
5) Disperse uniformly with a mixer with 2 parts by weight,
The mixture was kneaded with a kneader at a temperature of .degree. C., pulverized and classified, and 0.3 parts by weight of fine silica powder (HVK-2150, manufactured by Hoechst) was added and dispersed to obtain a toner having an average particle diameter of 10 .mu.m. A ferrite carrier (manufactured by Powder Tech, TY-10) was used so that the toner concentration was 5% by weight with respect to the obtained toner.
0) was mixed to obtain a two-component developer. The obtained two-component developer was used in a commercially available electrostatic copying machine for plain paper (FP-
1680) to prepare an image, which was used as a sample. Using this sample, the light stability and the decolorability as physical properties of the decolorable toner were examined according to the following methods. Table 1 shows the results.

[Light stability]: The reflection density of the obtained sample was measured using a Macbeth densitometer (= density A). After the sample was left under a 1500-lux fluorescent lamp for 24 hours, the reflection density was measured in the same manner as described above (= density B). Light stability was evaluated by the retention of concentration. (Retention) = (Concentration B) / (Concentration A) × 100 A: Retention is 90% or more B: Retention is 60% or more and less than 90% C: Retention is 30% or more and less than 60% D: Retention Is less than 30%

[Discoloration property]: The obtained sample was immersed in chlorine water for 72 hours at an atmosphere temperature of 40 ° C under the conditions shown in Table 1 or exposed to chlorine gas to visually confirm the discoloration property. A: Decolored B: Slightly decolored

[0014]

[Table 1]

[0015]

As described above, according to the present invention, by using a pigment excellent in heat resistance and light resistance as a colorant,
By immersing the formed image in chlorine water or exposing it to chlorine gas, an electrophotographic toner and a developer that can be erased can be obtained.

Claims (3)

(57) [Claims] 1. An inorganic pigment, spinel green or
Is a pyrrolopyrrole colorant, an organic pigment, a binder
-In electrophotographic toner composed of resin and additives ,
A decolorizable electrophotographic toner, wherein the image formed product is decolorized by chlorine-containing water or chlorine-containing gas. 2. A toner and calibration for electrophotography of claim 1, wherein
An electrophotographic developer using the rear . 3. An inorganic pigment, spinel green or an organic pigment, depending on chlorine-containing water or chlorine-containing gas.
A method for decoloring an image formed using an electrophotographic toner comprising a certain pyrrolopyrrole-based coloring agent, a binder resin, and an additive.