JPH02289859A - Production of nonmagnetic one-component developer - Google Patents

Abstract

PURPOSE:To obtain the nonmagnetic one-component developer having excellent flowability and developability by specifying the amt. of the hydrophobic silica to be added to a toner and the circumferential speed of the agitating vanes of a high-speed flow type mixer and sticking the hydrophobic silica in a partially flocculated state onto the toner surface. CONSTITUTION:The hydrophobic silica is added at 0.5 to 2.0wt.% to the toner and is treated for 1 to 10 seconds by means of the high-speed flow type mixer and by rotating the agitating vanes thereof at 30 to 80m/sec circumferential speed, by which the nonmagnetic one-component developer sticking to the toner surface in the partially flocculated state is obtd. The hydrophobic silica sticks weakly and nonuniformly in the partially flocculated state to the toner surface of this developer and, therefore, the electrostatic force is lowered by increasing the distance between the toner particles and the contact points are decreased. The flowability is improved in this way and the mirror image power with a carrier is lowered. The splashing to electrostatic latent images is improved and the developability is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a developer for an electrophotographic device, and more particularly, to a developer for a non-magnetic one-component developer made of a non-magnetic toner used in a non-magnetic one-component development system. This relates to a manufacturing method.

(Prior Art) It is well known that hydrophobic silica is added to toner as an electrophotographic developer to prevent the developer from filming on the photoreceptor and to improve fluidity. It is disclosed in Japanese Patent Publication No. 54-16219 and the like.

On the other hand, after the developer is supplied onto the carrier and a developer layer is formed by a layer forming member, it is transferred to a holding member that holds the electrostatic latent image, and the developer is attached to the electrostatic latent image to develop it. In the non-magnetic one-component development method, the toner's chargeability and fluidity are the most important factors in providing good development characteristics.
For this reason, the above-mentioned method of adding hydrophobic silica to toner is commonly used. However, in the non-magnetic one-component development system, the amount added conventionally is either too much, one, or conversely too little, and sufficient developability could not be obtained. In addition, the sufficient amount of addition has not been elucidated, and the effective addition conditions have not been elucidated, and the treatment methods have conventionally been gravity drop methods such as V-type mixers and tubular mixers. A mixer was used (Japanese Unexamined Patent Publication No. 58244/1983), but even with such a mixer, good development characteristics in non-magnetic one-component development could not be obtained.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to
The purpose of the present invention is to investigate the cause of this problem and provide a method for producing a non-magnetic one-component developer that has excellent flux and developability.

(Means for Solving the Problems) According to the research conducted by the present inventors, in order to obtain a non-magnetic one-component developer with excellent fluidity and developability, it is necessary to simply add hydrophobic silica to the toner as in the past. It has been discovered that merely adding and mixing is not sufficient, and that the state of adhesion is an important factor. In other words, hydrophobic silica adheres to the toner in a partially aggregated state, which increases the distance between toner particles, reduces electrostatic adhesion, and reduces the number of contact points, further improving fluidity. We also discovered that the mirror image force with the carrier is reduced, resulting in better flying force to the electrostatic latent image and higher developability. They discovered that there is an optimal range for the amount added, and that the method of mixing and stirring is extremely important, leading to the completion of the present invention.

That is, the developer used in the non-magnetic one-component development system according to the present invention contains 0.5 to 2.0% hydrophobic silica to the toner.
Hydrophobic silica is added to the toner surface in a partially aggregated state by adding 0% by weight and controlling the circumferential speed of the stirring blade and stirring time in a high-speed fluid mixing ram. It is.

Hereinafter, the method for producing a non-magnetic one-component developer of the present invention and various aspects of the present invention will be explained in detail.

First, the method for producing a non-magnetic one-component developer according to the present invention will be explained. In order to obtain the above-mentioned developer, 0.5 to 2.0% by weight of hydrophobic silica is added to the toner. , by using a high-speed fluid mixer, rotating the stirring blade at a circumferential speed of preferably 30 to 80 m/sec.
Manufactured by processing for 0 seconds.

Here, the high-speed fluid mixer is a type of mixer in which the blades attached to the bottom of the mixing container are rotated at high speed, and the powder and granules are dispersed in a ryuko-like manner by the blades' strong shear and impact action. This refers to a mixer.

A typical example is the Ciel mixer.

The toner used in the present invention is a thermoplastic resin such as styrene-acrylic resin, epoxy resin, polyester resin, etc., in which carbon, etc. as a coloring agent is dispersed in an amount of 5 to 20% by weight. ~2011m can be used. In some cases, polarity control agents,
For example, a nigrosine dye, a metal-containing azo dye, or a resin having a polar group may be added.

Examples of the hydrophobic silica used in the present invention include dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyl phenyldichlorosilane, benzyldimethylchlorosilane, prommethyldimethylchlorosilane, p-chlorophenyltrichlorosilane, Examples include colloidal silicon dioxide treated with hydrophobizing agents such as chlorobrobyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and divinyldichlorosilane, particularly dimethyldichlorosilane.

According to the present invention, hydrophobic silica is required to adhere to the toner surface weakly, non-uniformly, and in a partially aggregated state. Therefore, the optimum conditions for the treatment method will be described below.

(Test Example 1) This test examined the suitability of the mixer used and the influence of its processing time on the fluidity of a non-magnetic one-component developer.

The toner is styrene-acrylic resin (SSM-
73F, manufactured by Sanyo Chemical Co., Ltd.) and 10 parts by weight of Carphone Black (MA-100, manufactured by Mitsubishi Chemical Co., Ltd.) were mixed, ground, and classified to a particle size of 5 to 20 pm.

As a mixer, a V-type blender and a high-speed fluid mixer (Hensiel) were used, and the toner was mixed with hydrophobic silica (R97).
2. (manufactured by Nippon Aerosil Co., Ltd.) was added in an amount of 1% by weight, mixed and stirred, and the angle of repose was measured for each treatment time. The results are shown in FIG.

As is clear from Fig. 1, the fluidity of the obtained developer (
Although the angle of repose (angle of repose) varies depending on the processing time, it can be seen that it is best when the V-type blender is used for 10 minutes or more, and for the Heshishel mixer it is best when the processing time is between 1 and 10 seconds. Therefore, the conventionally used V-type blender is not as effective as the Hennschel mixer, and a high-speed mixer is optimal for producing non-magnetic one-component developers, and the processing time in that case is 1 to 10 seconds. is preferred.

(Test Example 2) This test shows the influence of the circumferential speed of the stirring blade of a high-speed flow mixer (Henshall) on the angle of repose (moatability) of the obtained developer.

Using a high-speed fluid mixer (Hensiel) as a mixer,
Mixing the same toner and hydrophobic silica as in Test Example 1,
The mixture was stirred and the angle of repose corresponding to the circumferential speed of the stirring blade was measured.

The results are shown in FIG.

From Figure 2, the peripheral speed of the stirring blade of the high-speed fluid mixer is 3.
It can be seen that the range of 0 to 80 m/sec is the best.

Similar to Test Example 1 above, when the surfaces of the developer (toner) obtained when processed with a conventional V-type blender and when processed with a high-speed flow type mixer were observed using a transmission electron microscope, it was found that there was no flow. It was observed that the state where the hydrophobic silica becomes high is a state where hydrophobic silica partially aggregates on the toner surface and adheres to a thickness of 20 to 100 μm.

The above test results are based on other resins, carbon, and various hydrophobic silicas (R972, R974 manufactured by Nippon Aerosil Co., Ltd.).
, R805, R812, and Taranox 500 manufactured by Talco) were used.

FIG. 3 shows the results of measuring the influence of the amount of hydrophobic silica added on the angle of repose of the developer.

As is clear from FIG. 3, the amount of hydrophobic silica added to the toner was best in the range of 0.5 to 2.0% by weight.

(Function) According to the present invention, 0.5% of hydrophobic silica is added to the toner.
~2.0% by weight is added and treated with a high-speed fluid mixer for 1 to 10 seconds by rotating the stirring blade at a circumferential speed of 30 to 80 m/sec. Hydrophobic silica is partially deposited on the toner surface. A non-magnetic one-component developer adhered in a cohesive state is obtained. In this developer, hydrophobic silica adheres to the toner surface weakly, unevenly, and in a partially agglomerated state, so as the distance between toner particles increases, the electrostatic adhesion force decreases. There are fewer contact points and fluidity is further improved. As a result, the mirror image force with the carrier is reduced, the flight to the electrostatic latent image is improved, and as a result, the effect of improving the developability is obtained.

(Example) The present invention will be specifically described below with reference to Examples and Comparative Examples.

(Example 1) Styrene - 100 parts by weight of acrylic resin (TB-1000, manufactured by Sanyo Kasei Co., Ltd.), 501 parts by weight of styrene butadiene resin (2-ball 200 sword, Nippon Zeon Co., Ltd.), polypropylene oligomer (Viscol 550ρ, Sanyo (manufactured by Kaseisha)
Fa. 4IIC:-person, 180°
The mixture was kneaded at C for 30 minutes, pulverized, and classified to obtain a toner with a size of 5 to 20 μm.

To the above toner, 1.OMIL% of hydrophobic silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) was added, and a high-speed flow mixer (Hensiel FB-20B type, manufactured by Mitsui Miike Industries, Ltd.) was added.
The developer was stirred for 5 seconds at a circumferential speed of 60 m/sec to obtain a non-magnetic one-component developer of the present invention having an angle of repose of 30°.

When this non-magnetic one-component developer was put into a non-magnetic one-component developing apparatus shown in FIG. 4 and tested, clear and uniform images were obtained.

In FIG. 4, 1 is a hopper for storing a non-magnetic one-component developer 5, 2 is a forming member, 3 is a carrier for carrying the developer, and 4 is a holding member for holding an electrostatic latent image. , the electrostatic latent image is charged to a surface potential of about 800V. In addition, the holding member 4 and the carrier 3 are
It rotates at 0mm/sec.

(Comparative Example 1) A non-magnetic one-component developer was produced in exactly the same manner as in Example 1 except that the processing time of the high-speed fluid mixer was changed to 30 seconds. It was bad sex. When this developer was tested in the same manner as in Example 1, it was difficult to fly to the electrostatic latent image and a uniform image could not be obtained.

(Effects of the Invention) According to the manufacturing method of the present invention, hydrophobic silica can be attached to the toner surface in a partially aggregated state.
The toner had excellent liquid mobility, and good development characteristics could be obtained in a non-magnetic one-component developing device.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the processing time of a high-speed fluid mixer and the angle of repose of the obtained non-magnetic one-component developer, and FIG. 2 is a graph showing the relationship between the circumferential speed of the stirring blade and the angle of repose. FIG. 3 is a graph showing the relationship between the amount of hydrophobic silica added and the angle of repose, and FIG. 4 is a schematic illustration of a developing device in which the non-magnetic one-component developer of the present invention is used.

Claims (1)

[Claims] (1) In a non-magnetic one-component developer characterized in that hydrophobic silica is attached to the toner surface in a partially aggregated state, the amount of the hydrophobic silica to the toner is 0.5 to 2.
．． 0% by weight, and the peripheral speed of the stirring blade in the high-speed fluid mixer is set at 30 to 80 m/sec, so that the hydrophobic silica adheres to the toner surface in a partially aggregated state. A method for producing a non-magnetic one-component developer.