JPS6388566A - Production of toner for electrophotography - Google Patents

Abstract

PURPOSE:To permit development by a simultaneous method and transfer to plain paper by a corona transfer method by passing thermoplastic resin particles through a narrow spacing and rapidly cooling the same right after the passage therethrough to stick insulating resin particles partially to the surface of the thermoplastic resin particles, thereby producing a flat toner. CONSTITUTION:An image forming body 6 laminated with a photoconductive layer 3, a transparent conductor layer 4 and transparent base layer 5 in this order is subjected to image exposing 8 at the time of moving in the direction of an arrow 7. A toner layer 11 is brought into contact with the body 6 in an exposing part by a magnetic brush formed by using a magnet roller 9 and a sleeve 10 and a bias voltage is kept impressed to the sleeve 10. Electric charge is, therefore, injected into the toner in contact with the body 6 through the electric current path formed by the contact of the conductive parts in the direction 12 of the electrical conductivity by the conductive parts 1 possessed by the respective toner particles with each other. The quantity of the electric charge is different in the exposed part and the unexposed part and a difference is eventually generated in the electrostatic attraction power of the toner to the surface of the photoconductive layer, by which the image is formed. The property to permit the selective use of the insulating characteristic and the electrical conductivity is thereby realized as the toner of the simultaneous method.

Description

[Detailed description of the invention] [Fields of use on the beach] The present invention relates to toners used in electrophotography.

[Conventional technology]

Traditionally, the toner used in child photography is used as a toner.

Insulating non-magnetic toners used in two-component magnetic brush development and float VL effect imaging methods, insulating magnetic toners used in jumping development, and conductive magnetic toners used in electrofax machines are known.

In addition, recently, a method of forming an image by simultaneously performing exposure and development (hereinafter referred to as the "simultaneous method"), which has the potential of greatly simplifying image processing, has been studied in various places. 153957. In this method, a bias voltage is applied and a brush of specific conductive magnetic toner is used to rub the surface of the photoconductor during exposure. The charge injected into the toner in contact with the photoconductor surface due to the bias voltage differs greatly between when it acts as a conductor (in the exposed area) and when it acts as a conductor (in the exposed area), and the amount of charge varies greatly. The difference in the amount of electrostatic charge l'Lt deposited on the photoconductor surface makes development possible.

[Problem that the invention attempts to solve] [7] However, due to its conductivity, the toner used in the simultaneous method can neutralize its charge in a short relaxation time and lose its residual charge. The well-known corona transfer method has the drawback that the toner cannot be transferred sufficiently to the paper.

The purpose of the present invention is to improve the current prisoner's law. /,'' - We provide toner that can be transferred onto plain paper using a flexible transfer method.

[Solving problems - means to solve problems]

The manufacturing method of tri-m=1 of the present invention involves dispersing the resin particles in a heat-resistant liquid maintained at a temperature higher than the softening point of the conductive thermoplastic resin. Immediately after passing through the narrow gap and passing through the vaginal gap, the thermoplastic resin particles are rapidly cooled, and the light surface of the hindlimb thermoplastic resin particles is partially coated with a tightening/relaxing resin particle with an I'' shape to flatten it. 1 hour to make → ~-
It is characterized by

[Effect]

By heating the conductive thermoplastic resin to a temperature above its softening point, the conductive thermoplastic resin becomes easily deformable. , #4 Because the conductive thermoplastic resin particles are dispersed in the thermal liquid, they are completely separated and do not aggregate together.
The heat-resistant liquid also works effectively for heat propagation and grain transportation. Each particle/lSlS metal mold passes through a gap narrower than the particle size, where the particles agglomerate with each other. Is this deformed state due to rapid cooling? '-Fixed and flat particles are obtained. Due to the anisotropy caused by the flatness, the f-u posture of the particles is defined, and the insulating particles can be attached to a certain part.For this reason, the toner is used as a simultaneous method.

Therefore, it is extremely useful because it can realize properties that allow for proper use of insulation and conductivity.

〔Example〕

According to the present invention in Figure 1! 8! An example of crushed electrophotographic toner is shown. Figure 1 (σ) shows the external view, Figure 1 (b)
shows its cross-sectional view. As described above, the toner of the present invention has a flat disk shape, and the toner 11!
Part 1 is exposed and the other parts are covered with insulating part 2. FIG. 2 shows how an image is formed using the toner of the present invention. An image forming body 6 formed by laminating a photoconductor layer 3, a transparent conductor layer 4, and a transparent support layer 5 in this order receives image exposure 8 as it moves in the direction of an arrow 7. Magenevtroller 9
The well-known brush j which is shaped using the sleeve 10 and
The image forming body 6 is then drawn on the base of the toner layers 111d-g.
It is in contact with A bias voltage of 12h is applied to the sleeve 10;
The toner that is in contact with the image forming experience has a conductive portion 1 that each toner has! A charge is injected through the current path formed by the contact K between the conductive parts in the conductive direction 12 (i.e. the contact between the ends of the disk). The amount of charge injected in the exposed area and the unexposed area is h'-
As a result, the electrostatic adhesion of toner to the surface of the photoconductor layer results in a difference in adhesion and image formation. FIG. 5 shows the state of electrostatic transfer using the toner of the present invention. Image forming body 6
It is moving in the direction of arrow 16. Toner image h: A transfer waste paper 1311I is superimposed on the surface of the image forming body 6 on which the image has been formed, and a corona transfer device 14 transfers toner charge (injected during image formation) and idle charge from the back side of the transfer paper 13. Ions are implanted. At this time, the toner particles 15 on the i1i'i image forming body 6 are falling down in a stable position. As a result, the insulating portion 2 and the transfer paper 156 come into contact. 1. When viewed from the transfer paper 15, the toner is charged P! As the edge body is similar to the one shown in FIG.

Next, the method for manufacturing the toner of the present invention will be described in detail.

First, a predetermined amount of a thermoplastic resin, a coloring material, a conductive rate adjusting material, and a magnetic material are mixed and dispersed using a mixer. This styrene resin is a well-known elastic thermoplastic resin.

Some polymers, polyester, polyethylene, polypropylene, acrylic resin, polyvinyl acetate, polyurethane, polyamide, epoxy resin @.

Polyvinyl chloride, polyvinyl butyral, boriamite, rosin, modified rosin, terpene resins, phenolic resins, aliphatic or aliphatic hydrocarbon resins.

Aromatic petroleum resin, chlorinated paraffin, etc.b; Can be used in combination. As the coloring material, carbon black, nigrosine, etc. can be used.

Carbon black, metal powder-metal fiber, etc. are used as the conductivity adjusting material. Compounds such as magnetite, hematite, and fuemoite are known as magnetic materials.1. The mole used is an alloy of metals such as iron, cobalt, and nickel.This kneaded material has a high conductivity so that electrical charge can be injected. X lumber t: Mixed.

Next, it is coarsely pulverized, then finely pulverized using a Gevt airflow pulverizer, and then classified to obtain conductive fine powder with uniform particle size (FIG. 4 (σ)). Next, the conductive fine powder is dispersed in a heat-resistant liquid, such as a silicone-based liquid or a fluorine-based liquid. After this, raise the temperature of the heat-resistant liquid to above the softening point of the conductive fine powder. At this point, the conductive fine powder exhibits fluidity and becomes rounded (FIG. 4(b)). Next, this liquid is passed through a gap narrower than the particle size of the conductive fine powder and immediately thereafter rapidly cooled to below the softening point of the conductive fine powder.

In this way, the conductive fine powder becomes spherical and then flattened and flattened, and the particle shape is fixed in its regular shape and becomes a disk shape (FIG. 4(C)). In order to perform this cooling reliably, the gap may be constructed with both cooled rolls. After this, the conductive fine powder is taken out from the heat-resistant liquid.

Disc-shaped conductive fine powder and insulating fine powder particles 1
7 (particle size approximately 1 irm) and attach insulating fine particles 17 around the conductive fine powder in a ball mill (
Figure 1).

After that, the insulating fine particles are melted in a hot air stream to increase the adhesion strength between the insulating fine particles 17 and the conductive resin surface.
- (Figure 4(e)). Next, the conductive fine powder on which the insulating fine particles have been deposited is placed in a ball mill and made to collide with each other. As a result of this process f, the insulating fine particles at the disk-shaped end of the conductive fine powder are peeled off I-, and the conductive resin is exposed at the disk end. This always happens because the edge of the disk collides strongly and frequently with other particles. Thus, the toner 7 of the present invention
1″-Done (Figure 4 (c)).

Next, one production example of the present invention is shown. 100 parts by weight of acrylic, 50 parts by weight of magnetite, and 10 parts by weight of conductive carbon black were mixed, kneaded in a screw extruder, and then crushed and classified to have a diameter of 9 to 13 μm. powder is obtained. Since the colorant also serves as carbon black, it is not added in this example. The specific resistance of this resin is 2x
10', on the Qe side.

This is dispersed in silicone oil having a heat resistance of 300°C, and the liquid temperature of the silicone oil is set to 230 to 250°C.

At this stage, the softening point of the acrylic resin has been exceeded, and the powder resin exhibits fluidity and the corners of the particle surface are smoothed out. The conductive resin particles in this state were passed between twin rolls with silicone oil (with a gap of 5 μm). The twin rolls were sufficiently cooled.

While passing through twin rolls, it is cooled to below the softening point.

In this process, disk-shaped particles are obtained, the disk diameter is 10 to 18 μm and the thickness is usually 5 μm.

These particles and an acrylic resin with a diameter of 1 μm were mixed in equal weights and treated in a ball mill for 3 millimeters. In order to melt the surface of the conductive particles coated with insulating acrylic resin (
The sample is then treated for a short time in a hot air stream at 500°C. The post-treated particles are processed in a ball mill for 2 hours to complete a toner.

When I tried the simultaneous method using this toner, the transfer efficiency was 65.
~80 cm*M h” - obtained at 70-40% relative humidity compared to conventional resistivity 2 x 10'Ω
The transfer efficiency was 20 as a result of trying the simultaneous method with φ1 conductive toner.
Only .about.55 .mu.m of relative humidity [70-40 .mu.m] was obtained.

〔Effect of the invention〕

As mentioned above, the toner production method according to the present invention is suitable for the simultaneous method to obtain toner in a large amount./1? -Spell it with -. The significance of this is that by using the toner of the present invention, an unprecedentedly compact and low-cost electrophotographic printer will be realized, and everyone will be able to take advantage of its high speed and high print quality. There are extremely large ones.

[Brief explanation of the drawing]

FIG. 1(a) is an external view of a toner manufactured according to the present invention. FIG. 1(b) is a cross-sectional view of a toner produced according to the present invention. Figure 2 shows the inventive VC: 97u made toner? Diagram showing the image formation process according to the simultaneous method used. FIG. 5 shows the use of toner produced according to the present invention.
Case no Shizuka 111! Diagram showing the transcription process. FIG. 3 is a diagram illustrating the state of resin particles that become toner. 1...Conductive part 2...Insulating part 3...Photoconductor layer 4...Transparent conductor layer 5...Transparent support 6...1illii Image forming body 7... Moving direction of the image forming body 8...1 Tan light? ......Magnetic roller 10...Sleeve 11...Toner R vague 12...Bias voltage 13...Transfer paper 14...・Corona transfer device 15...Toner 16...Movement direction of image forming body 17...
・Transfer paper movement direction 18... Insulating fine particles or more Applicant Seiko Epson Corporation 2, retired 1P Figure 1 Figure 2 Figure 3 (α) (Figure 4 (C) , Co (f)

Claims (1)

[Claims] The thermoplastic resin particles dispersed in a heat-resistant liquid maintained at a temperature equal to or higher than the softening point of the conductive thermoplastic resin are passed through a gap narrower than the particle size, and immediately after passing through the gap, the thermoplastic resin particles are A method for producing an electrophotographic toner, which comprises rapidly cooling the thermoplastic resin particles, and then partially adhering insulating resin particles to the surface of the thermoplastic resin particles to produce a flat toner.