JPS6115154A - Toner for photosensitive body of amorphous silicon - Google Patents

Abstract

PURPOSE:To polish moderately the surface of a photosensitive body of a-Si to such a degree that the printing resistance is not reduced and to form a latent image on the sound and fresh surface by adding externally silicon carbide powder of a specified particle size to the surface of a toner for converting an electrostatic latent image formed on the surface of the photosensitive body into a visible image. CONSTITUTION:Hyperfine silicon carbide powder of 0.1-1mum average particle size is added externally the surface of a toner for converting an electrostatic latent image formed on the surface of a photosensitive body of a-Si into a visible image by 0.05-5wt% of the amount of the toner so that the surface of the photosensitive body can be polished by making use of rubbing force during development or cleaning. Since the silicon carbide polishing agent has surface hardness almost equal to that of the photosensitive body and is hyperfine powder, the surface of the photosensitive body is not excessively polished and does not take such scratches as to exert unfavorable influence on an image. The surface of the photosensitive body is moderately polished to such a degree that the printing resistance is not reduced, and a latent image can be formed on the sound and fresh surface at all times, so a clear image is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a toner in a one-component or two-component developer, and more particularly to a toner suitable for a system using an amorphous silicon photoreceptor. It is something.

Technical Background In commercially available electrostatic copying machines and laser printers, a widely adopted method is to imagewise expose the surface of a charged photoreceptor and develop the formed electrostatic latent image with toner to make it visible. has been done.

When this copying system is employed, the surface of the photoreceptor is destined to gradually deteriorate due to various causes during repeated use. Examples include film quality deterioration due to exposure of the corona charger during the charging process, and surface deterioration due to filming of toner components due to rubbing between the toner and the photoreceptor during the development process.

Due to these surface deterioration phenomena, the electrophotographic properties such as charging ability and sensitivity that the photoreceptor originally has are reduced.

In commercially available copying machines and the like, selenium photoreceptors and cadmium sulfide photoreceptors are used as photoreceptors, and the surfaces of these photoreceptors deteriorate due to repeated copying processes. However, fortunately, the hardness of the surface of these photoreceptors is not extremely high, and the deteriorated photoreceptor surfaces are gradually polished and scraped off by various sliding forces during the copying process. As a result, a new surface is constantly exposed, and deterioration of electrophotographic characteristics due to surface deterioration is effectively masked. This phenomenon is masked to the extent that it does not pose a problem in systems using cleaning blades, which have been widely adopted in copying systems in recent years.

However, these photoreceptors are difficult to handle because the surface of the photoreceptor is not very hard, so they are prone to paper jams during use and scratches from carriers (iron powder and ferrite powder) during development, and they are difficult to handle. The number of copies is low, on the order of tens of thousands of copies at most.

As a result, a photoreceptor with higher surface hardness and superior printing durability and handling properties has been desired, and the use of an amorphous silicon photoreceptor has become particularly desirable.

This amorphous silicon photoreceptor has high surface hardness and fast sensitivity, so it is a photoreceptor with excellent printing durability.

However, a phenomenon has been observed in which the surface of this amorphous silicon photoreceptor is also exposed to radiation from the corona charger during charging and gradually deteriorates. In other words, the deterioration phenomenon A in silicon photoreceptors is caused by image blurring (occurred by leakage of surface charges toward the film surface) due to the photoreceptor surface becoming hydrophilic and adsorption of water molecules. This is a phenomenon (disappearance of latent image charge that occurs). Since the hardness of amorphous silicon is high, this deteriorated surface W layer cannot be polished by the rubbing force during the copying process.

The object of this invention and the present invention are that even when an amorphous silicon photoreceptor is used, the surface of the photoreceptor is appropriately polished to the extent that printing durability is not reduced, and a latent image can be formed on a new surface that does not constantly deteriorate. The purpose is to provide improved technology to enable this. That is, the present inventors have achieved the above object by selecting a specific abrasive and externally adding it to the surface of the toner.

According to the present invention, as a toner for visualizing an electrostatic latent image formed on the surface of an amorphous silicon photoreceptor, an average particle size of 0.05 to 5% by weight per toner is used. There is provided a toner for an amorphous silicon photoconductor characterized in that silicon carbide of 0.1 to 1 μm, more preferably 0.1 to 0.5 μm, is externally added to the surface of the toner.

-Kimitsu Nori■ Sole 1 In the configuration of the present invention, the abrasive has an average particle size of 0.
A notable feature is the use of ultrafine silicon carbide powder of 1 to 1 μm, which has never been seen before.

Silicon carbide as an abrasive is known as carborundum. However, this well-known carborundum has a large average particle size of 2 μ or more. When using carborundum with a large particle size as an abrasive, the polishing conditions must be strictly controlled or the surface of the photoreceptor will be excessively abraded, so it cannot be used in a method where it is added to the developer and constantly polished. It's something you can't get. This is because the larger the average particle diameter, the greater the amount of polishing, which particularly reduces the printing durability of conventional selenium-based photoreceptors and causes scratches on the surface of the photoreceptor.

In the present invention, these drawbacks are prevented by using the ultrafine silicon carbide described above, and the frictional force during development or cleaning is utilized by a simple method of externally adding it to the surface of the developer, especially the toner. This made it possible to perform constant polishing.

Furthermore, since silicon carbide used as an abrasive has a surface hardness comparable to that of an amorphous silicon photoreceptor, if ultrafine powder is used, excessive polishing may result in scratches that may affect the image. It has the characteristic that there is no problem at all.

As the developer used in the present invention, either a -component magnetic toner or a two-component developer consisting of a toner and a carrier can be used. External additive processing is 0.05 per toner
Silicon carbide fine powder is added in an amount of 3 to 3 parts by weight, and dry blending is performed using a stirring means such as a mixer to electrostatically hold the powder on the toner surface. In order to further strengthen the retention, the dry blended toner can be treated with hot air to embed fine silicon carbide powder on the surface of the toner. In addition, in the case of three-component developer,
Instead of dry blending only with the toner, it is of course also possible to dry blend with a carrier so that the toner is retained on the toner surface within the above-mentioned range.

In the present invention, the silicon carbide fine powder used is available from Taiheiyo Random Co., Ltd. 31, for example.

As the amorphous silicon photoreceptor for use in carrying out the toner of the present invention, any known amorphous silicon photoreceptor may be used.
For example, amorphous silicon deposited on a substrate by plasma decomposition of silane gas is used, and this material is
It may be doped with +gen, etc., and further doped with an element of group 1 or group 2 of the periodic table, such as boron or phosphorus.

The physical properties of typical amorphous silicon photoreceptors are dark conductivity (IQ-12Ω-”Cff1-’, activation energy <0.85, v, photoconductivity >10-’Ω-1・C
u11-', optical bandgap 1.7-1.9.
V, the amount of bound hydrogen is 10 to 20aLom%, and the dielectric constant of the film is in the range of 11.5 to 12.5.

As amorphous Noricon photoreceptors having such physical properties, those having a surface layer made of solicon nitride (a5iN) or silicon carbide (a-3iC) are particularly preferred. The reason for this is that the surface hardness is higher than that of amorphous hydrogenated silicon, and it has a hardness comparable to that of silicon carbide fine powder used as an abrasive. This is because it becomes possible to polish the layer.

The invention is illustrated by the following example.

ltU [-Seeheimer SBM-73 (styrene resin; manufactured by Koshu Kasei Kogyo Co., Ltd.)...87 parts by weight Viscoel 550P (low molecular weight polypropylene; manufactured by Koshu Kasei Kogyo Co., Ltd.)...5
Part by weight Special Black 4 (carbon black; manufactured by Degussa)...5.5 Part by weight Bontron 5
-32 (dye; manufactured by Orient Chemical Co., Ltd.)
...1.5 parts by weight The mixture having the above composition was thoroughly melted and mixed and dispersed in a heated three-roll mill, and then the kneaded product was taken out and cooled, and then crushed in a coarse grinder (Rotoplenox knotting mill: manufactured by Alpine). ) to a size of about 2 mm, and then an ultra high-speed jet mill (NIIIPON P
NEIIMAT (manufactured by CMFCCo, LTD) was pulverized with -C, and a toner having a particle size of about 5 to 20 μm was prepared by a classification operation.

To this toner, silicon carbide (manufactured by Pacific Random) fine particles having an average particle size of 0.3 μm were added at a ratio of 0.3% by weight, mixed thoroughly, and D-Sill;
A developer was prepared by mixing this toner at a ratio of 8.0% by weight with a 250 mesh ferrite carrier having a resistivity of 3.5×10′Ω.

Separately, a similar developer was prepared by making a toner using hydrophobic silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) instead of silicon carbide.

It should be noted that the D-3 resistance of the carrier as used herein is an electrical resistance value dynamically measured under development conditions using only a carrier with a magnetic brush, and means a value determined by the method described below. That is, an aluminum electrode drum of the same size as the electrophotographic photoreceptor drum is installed in place of the photoreceptor drum, developer is supplied onto the developing sleeve to form a magnetic brush, and this magnetic brush is rubbed with an electrode drum. Rubbing-C3 means the resistance value calculated by applying a voltage between the sleeve and the drum and measuring the current flowing between them. In this case, the measurement conditions were: applied voltage 50 V, photoreceptor drum length 30 cm, diameter 9 cm, distance between drum and developing sleeve 1.5 m+, spacing between ears 1.0 ml11, drum rotation circumferential speed clockwise 16 cm/ SEC, sleeve rotation peripheral speed clockwise 23 cn/SEC was used.

Next, a copying test was conducted using the prepared developer.

The copying device was set and used under the following conditions.

Photoreceptor: A-3i:It doped with boron was deposited on a substrate made of 90 mmA diameter to a film thickness of 20 μm by glow discharge decomposition.Light source for image exposure; Light intensity on the surface of the photoreceptor 60μW/cIII (but above 600nm)
Static neutralizing light source: Cold cathode discharge tube that emits green light. Cleaning section: Blade cleaning force type. Main charging: Corona charger (applies +6.2 KV). Transfer charging: 〃
(+5.7 KV applied) Copying speed: Photoreceptor drum rotation speed 16 cm / SEC developing section Nisleeve rotation speed 23 cm / SEC developing magnet strength 1
000 Gauss Spike cutting interval 1.0 mm Development area: Rotate both the photoreceptor (D) and the development sleeve (S) clockwise, and the gap between D-3 is 1.5 mm.
Fixed.

In the copying test, continuous copying was performed using an A4 size text original in an environment with a room temperature of 25° C. and a relative humidity of 70%, and changes in the copied images were examined. The developer using the toner of the present invention did not cause any abnormality in the image even after copying 100,000 sheets of A4 size paper. However, the developer using the conventionally known hydrophobic silica added From page 1 onwards, the copied text began to distort, and the phenomenon of so-called image smearing began to become noticeable. Furthermore, when looking at the drum surface, a thin layer that appeared to be toner filming was formed, but this was not observed with the above-mentioned developer.

The amount of silicon carbide mixed is 0.
It was found that below the 2005 economic downturn, the effect is weak, and when it is above 5% by weight, the color of the copied text may appear slightly greener than black, possibly due to the green color of the silicon carbide, which is not preferable.

It was also shown that the smaller the phosphoric acid l' fine particles, the better the effect, and preferably the average particle diameter was 1 μm or less.

Example 2 Petroleum resin (Mitsui Oil Co., Ltd., Hirenotsu 1-100L1)
00L parts by weight, polypropylene (manufactured by Bonsaku Kasei) 3
5 parts by weight and 35 parts by weight of magnetite having a coercive force of 85 oersted, a bulk density of 0.371;/m#, and an average particle size of 0.3 to 0.4 μ are dissolved and dispersed in hot toluene as a solvent, and after spray drying. , classification is performed to obtain a magnetic toner having a particle size of 5 to 25 μm.

100 parts by weight of this magnetic toner and 0.8 parts by weight of carbon black (manufactured by Mitsubishi Chemical Industries, Ltd.) were mixed in a ■-type mixer, and then sprinkled with silicon carbide fine particles with an average particle size of 0.5 μm. It is added in a proportion of 5% by weight and thoroughly mixed to form a conductive component magnetic developer.

In the copying machine used in Example 1, a copying test was conducted by changing the developing section to one for use with a single-component developer. That is, the strength of the magnetic field on the developing sleeve (outer diameter 331) containing a built-in magnet via a non-magnetic member is set to about 900 Gauss, and the developing roller is of a so-called dual rotation type in which the magnet and sleeve can be rotated independently. The above-mentioned magnetic toner was deposited on top with a gap of 0.3 mm between the cutting plate and the sleeve, and the magnetic toner was arranged so that it could be supplied from the popper to the developing roller section, and the gap between the photoreceptor surface and the developing roller was 0.5 mm.
And so. Charging (+6.7 KV), exposure, development, and transfer (+6.3
K v), heater roller fixing and cleaning were performed. Processed paper with a thickness of 80 μm was used as the transfer paper.

A copy test was conducted in the same manner as in Example 1, and 10 copies were made on A4 paper.
Although I made 10,000 copies, I did not find any abnormalities such as image blurring in the images.

Claims (1)

[Claims] 0.05 to 5% by weight per toner as a toner that visualizes the electrostatic latent image formed on the surface of the amorphous silicon photoreceptor.
1. A toner for an amorphous silicon photoreceptor, characterized in that silicon carbide having an average particle size of 0.1 to 1 μm is externally added to the surface of the toner in an amount ratio of 0.1 to 1 μm.