JPH07120074B2 - Method for manufacturing toner for electrophotography - Google Patents

Description

The present invention relates to a method for producing an electrophotographic toner, and more specifically, it relates to a charging method with less fog and excellent stability of image density. The present invention relates to a method for producing a toner having a sharp amount distribution.

(Prior Art) As an electrostatic charge developing method, a method using a two-component developer in which toner particles are mixed with carrier particles, that is, glass beads or magnetic powder, and one component in which toner particles themselves are magnetized There is a method of using a system toner, and more recently, a method of using a non-magnetic one-component toner excellent in environment resistance has been proposed.

Conventionally, this toner for electrophotography is prepared by premixing a thermoplastic resin with a colorant, a charge control agent, a wax, and the like, kneading with a disperser such as a twin-screw extruder, a triple roll, and a kneader, and roughly pulverizing after cooling, It was manufactured by finely pulverizing and classifying, and adding a fluidity improver and the like if necessary.

These toners have problems to be solved, such as presumed to be caused by poor dispersion of a colorant or a charge control agent, the image density is difficult to appear, and fog is generated. Kneading by applying a shearing force contributes to the above solution, but it is presumed that the molecular chain of the thermoplastic resin is broken, causing offset development of toner, deterioration of storage stability, and paper for fixing device. However, there are problems such as the involvement of the sword and the fundamental solution has not been made.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned various problems, is excellent in the dispersion of the colorant and the charge control agent, and is excellent in that there is no toner offset phenomenon. It is to produce a toner having performance.

[Structure of Invention]

(Means for Solving the Problems) In the present invention, the colorant and the wax are kneaded with a strong shearing force in the first step, and then the resin is mixed,
It is based on a new finding that conventional problems can be solved. That is, the present invention provides a first step of kneading a colorant, a wax and, if necessary, a charge control agent by applying a strong shearing force in a molten state of the wax, and a kneaded product, a resin and if necessary in the first step. A method for producing an electrophotographic toner characterized by using a colored chip obtained by a step including a second step of kneading other additives with a shearing force weaker than that of the first step. is there. The present invention is characterized in that a colorant, a charge control agent and the like are sufficiently dispersed with a wax in a first step with a strong shearing force, and then a resin is added to perform a weak kneading. It is characterized by eliminating the problem of and the problem of breaking the molecular chain of the resin.

The colorant in the present invention is not particularly limited, carbon black, phthalocyanine blue, phthalocyanine green, nigrosine dye, titanium black, red iron oxide, zinc yellow, Hansa yellow, disazo yellow, quinoline yellow, permanent yellow, permanent red. Uses pigments or dyes such as, Resole Red, Pyrazolone Red, Woochan Red Ca Salt, Woochan Red Mn Salt, Lake Red C, Lake Red D, Brilliant Carmine 6B, Brilliant Carmine 3B, Navy Blue, Titanium Oxide, Oil Black can do.

As the wax, paraffin wax, natural wax, synthetic wax and the like can be used.
PE-130 (trade name of Hoechst AG), Viscor 550P,
Same as 330P (trade name of Sanyo Kasei Co., Ltd.), Mitsui High Wax 44
0P, 200P (trade name of Mitsui Petrochemical Co., Ltd.), wax C
(Trade name of Hoechst AG), bisamide A (trade name of Nippon Kasei Co., Ltd.) and the like can be used.

As the charge control agent, a charge imparting dye of an azine-based nigrosine derivative as a positive charge control agent, a quaternary ammonium salt compound, specifically, nigrosine base EX, Bontron N-01, N-07, P- 51 (Orient Chemical Co., Ltd. trade name), Oil Black S (Chuo Synthetic Chemical Co., Ltd. trade name), etc. Also, as the negative charge control agent, a metal-containing azo dye or a non-pigmented metal There are electron-accepting organic complexes such as complexes, chlorinated paraffins, chlorinated polyesters, and copper phthalocyanine derivatives.
Bontron E-82, E-84, S-31, S-32 (trade name of Orient Chemical Co., Ltd.), Kayaset Black T-2, Kayacharge N-1, (trade name of Nippon Kayaku Co., Ltd.), Spiro Black TH
(Hodogaya Chemical Co., Ltd. product name), etc. can be used.

As the kneading machine which gives a strong shearing force used in the first step of the present invention, there are a heating three-roll, a heating two-roll, a Banbury mixer, a pressure kneader and an extruder, but in order to give a strong shearing force, The effect of viscosity at the time of kneading is important, and the mixing weight ratio of the colorant and wax
It is preferably 100/35 to 70.

As the thermoplastic resin used in the second step, polystyrene-based, styrene-acrylic acid ester, methacrylic acid ester, a copolymer system containing styrene such as acrylonitrile or maleic acid ester, polyacrylic acid ester-based, polymethacrylic acid Known binder resins such as ester-based, polyester-based, polyamide-based, polyvinyl acetate-based, epoxy-based resins, phenol-based resins, hydrocarbon-based resins and petroleum-based resins can be exemplified, and these can be used alone or as a mixture. Can be used.

In the present invention, when a magnetic toner is used, a magnetic powder known per se can be used, and various additives can be added if necessary.

In the second step, the same disperser as in the first step such as hot three-roll, hot two-roll, and a twin-screw extruder can be used. At this time, the solid content of the pigment, the charge control agent, etc. ,
When the amount is 3 to 25% by weight, the shearing force can be made weaker than in the first step.

The colored chips thus obtained can be pulverized and classified by a conventional method to prepare a toner for electrophotography according to the purpose.

The present invention will be described below with reference to specific examples. The middle part of an example shows a weight part.

Comparative Example 1 Styrene-acrylic resin (Arakawa Chemical Industry Co., Ltd. Lupenal 510, trade name) 87 parts, polypropylene wax (Sanyo Kasei Co., Ltd., Viscole 550P trade name) 5 parts, Bontron S-31 2 parts and Mogar 6 parts of 880R (carbon black manufactured by Cabot, trade name) was mixed with a Henschel mixer, and this was melted, kneaded and allowed to cool with a twin-screw extruder, and this kneaded material was roughly crushed to obtain colored chips.

This colored chip was subjected to a type I jet mill to obtain resin particles having an upper limit particle size of 25 μm or less and an average particle size of about 10 μm.

This toner is a particle charge amount measuring device (Hosokawa Micron Co., Ltd.)
Manufactured) and the results are shown in FIG.

To 100 parts of this toner, 0.3 part of silica fine powder (R-972, trade name of Nippon Aerosil Co., Ltd.) was added and mixed, and further ferrite carrier F-141-400 (trade name of Nippon Iron Powder Co., Ltd.) 900 The parts were mixed to prepare a two-component developer.

This developer is a commercial copying machine (trade name FP) manufactured by Matsushita Electric Industrial Co., Ltd.
−2520) and used the test chart to make continuous copies on plain paper. As a result, the initial image density was 1.35.
There was a tendency that it fell to 1.1 after 2,000 sheets, and when the charge amount of the developer at that time was measured (measuring machine manufactured by Toshiba Chemical Co.), the initial -24 μC / g was -15
It became μC / g.

Example 1 The same raw material as in Comparative Example 1 was used, and the method for producing a colored chip was changed as follows. That is, the raw materials excluding styrene-acrylic resin were mixed with a Henschel mixer, kneaded with a hot three-roll mill, and coarsely pulverized with styrene-acrylic resin mixed with a Henschel mixer, and melt-kneaded with a twin-screw extruder. Then, after cooling, it was roughly pulverized to obtain colored chips.

Thereafter, a toner was prepared in the same manner as in Comparative Example 1. The charge amount distribution of the toner is as shown in FIG. 2, and it is understood that the charge amount distribution is sharper and the amount of reversely charged toner is smaller than in Comparative Example 1.

In addition, 0.3% by weight of this toner was used in the same manner as in Comparative Example 1.
A silica developer R-972 and a ferrite carrier were added to prepare a developer.

The charge amount of the developer was -25 μC / g. As a result of a copying test using this developer in the same manner as the toner of Comparative Example 1, the fog was extremely small, and the density change was observed even after continuous operation of 40,000 sheets. It was possible to obtain an excellent image.

Example 2 90 parts of styrene-acrylic resin of Comparative Example 1, wax C4
Toner, 3 parts of Bontron N-01 and 4 parts of # 44 carbon black (trade name of Mitsubishi Kasei Co., Ltd.) were used to obtain a toner in the same manner as in Example 1. 0.1% by weight of this toner was obtained.
Silica R-972 was added as the final toner.

Using this toner, a copier for a one-component toner on the market (Ricoh Co., Ltd., trade name: M-10) was tested, and it was possible to obtain a copy with good image quality without fog and image density.

[Brief description of drawings]

FIG. 1 shows the toner of Comparative Example 1 manufactured by Hosokawa Micron Co., Ltd.
Product name) 12.5 in toner by applying charge amount distribution device
FIG. 2 is a graph showing a distribution of charge amounts measured for particles having a particle size of μ, 9.9 μ and 5.0 μ, and FIG. 2 is a similar graph for the toner of Example 1.

Claims (2)

[Claims] 1. A first step of kneading a colorant, a wax and, if necessary, a charge control agent in a molten state of a wax by applying a strong shearing force, and a kneaded product, a resin and, if necessary, in the first step. A method for producing an electrophotographic toner, which comprises using a colored chip obtained by a step including a second step of kneading other additives with a shearing force weaker than that of the first step. 2. The production method according to claim 1, wherein the mixing weight ratio of the colorant and the wax in the first step is 100/35 to 70.