JPH02101480A - Image forming method - Google Patents

Abstract

PURPOSE:To remove attached matter from a photosensitive body by rubbing with a magnetic brush and to prevent defects of image quality by using a magnetic toner containing a 3-30wt.% magnetic powder disclosed to the surface of the magnetic toner in an amount of 0.1-1.0% as an iron element. CONSTITUTION:The magnetic toner to be used contains a 3-30wt.% magnetic powder disclosed to the surface of the magnetic toner in an amount of 0.1-1.0% as an iron element. If the content of the magnetic powder is less than 3wt.%, image defects occur, and if more than 30wt.%, electric chargeability deteriorates and image defects occur, and the life of the toner is shortened. If the disclosed amount of the magnetic powder is <0.1%, the effect of removing an attached matter by rubbing is lowered, and if >1.0%, image defects due to the magnetic powder contained in the toner is caused, thus permitting stains on the surface of an electrophotographic sensitive body caused by transfer materials, such as paper, and a developer composition when an electrostatic latent image formed on the surface is developed, to be prevented and image defects to be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image forming method for visualizing an electrostatic latent image by electrophotography.

Conventional technology In electrophotography, an electrophotographic photoreceptor with a photoconductive material as a photosensitive material is used to form an electrostatic latent image by various means, and then the electrostatic latent image is transferred using a magnetic brush or the like. A method of attaching toner and visualizing it is generally adopted. The toner image developed on the photoreceptor is transferred onto a transfer material such as paper, while the toner remaining on the photoreceptor is cleaned and prepared for the next step.

Problems to be Solved by the Invention When the above electrophotographic method is carried out, talc contained in transfer materials such as paper may adhere to the photoreceptor, and toner additives may adhere to the photoreceptor. This deposit may cause image loss. In addition, particularly in high-speed copying machines, toner is scattered by magnetic brushes and the like, resulting in noticeable dirt inside the machine and causing maintenance problems.

The present invention aims to eliminate and improve the problems in the conventional techniques described above.

That is, an object of the present invention is to provide an image forming method capable of removing deposits on a photoreceptor by l'Ij[ using a magnetic brush and preventing image quality defects. Another object of the present invention is to provide an image forming method in which magnetic toner is less likely to scatter from a magnetic brush and does not cause stains inside the machine.

Means for Solving the Problems The present invention provides an image forming method in which an electrostatic latent image formed on an electrophotographic photoreceptor having an organic photoconductive layer is developed using a two-component developer consisting of a carrier and a magnetic toner. The magnetic toner is characterized in that it contains 3 to 30% by weight of magnetic powder, and the amount of exposed magnetic powder on the surface of the magnetic toner must be 0.1 to 1.0% as iron element. shall be.

The present invention will be explained in detail below.

The magnetic toner used in the image forming method of the present invention has a structure in which magnetic powder is dispersed in a binder resin.

As the magnetic powder, for example, powders of oxides such as iron, iron oxide, ferrite, etc. are used, and desirably, triiron tetraoxide, 14
Powders such as n-Znn Fushii 1~, Ni-Zn ferrite, and 8a ferrite are used. These magnetic powders have a particle size of 0.05~2.0p, preferably 0.1~1.0p.
It is used as a granular powder with a length of m or a needle-shaped powder with a major axis of 2.07 ffl or less.

Examples of the binder resin include styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl acetate:
α of methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, etc.
- Esters of methylene aliphatic monocarboxylic acids; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, etc. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, and styrene-butadiene copolymer. ,
Examples include polyolefins such as styrene-maleic anhydride copolymer, polyethylene, and polypropylene. Other polyester, polyurethane, epoxy resin,
Mention may be made of polyamides, modified rosins, and paraffin waxes.

In the present invention, the magnetic toner may contain a colorant. In addition, carbon black is used as a charge control agent.
A quaternary ammonium salt, an organic complex, etc. may also be included.

The magnetic powder is contained in the magnetic toner in an amount of 3 to 30% by weight, preferably 5 to 20% by weight. Magnetic powder content is 3% by weight
If it is lower than 30% by weight, image loss will occur, and if it is higher than 30% by weight, the charge amount will decrease, image loss will occur, and the life of the toner will be shortened.

Further, in the present invention, the magnetic powder is applied to the surface of the toner particles.
It is necessary that 0.1 to 1.0% of the iron element be exposed. If the amount of exposed magnetic powder is lower than 0.1%, the effect of removing surface deposits due to the sliding gap is low, and if it is higher than 1.0%, image loss may be caused by the magnetic powder contained in the magnetic toner. It will be done.

In the present invention, the amount of exposed magnetic powder is measured as follows.

Measuring device: JEOL! ! Wooden, X-ray photoelectron spectrometer PS
-80 Measurement conditions: X-ray double anode type Hg1253.
8eV used acceleration 10kV, 30mA Analyzer resolution: 30eV Target photoelectron: Fe 2p3/2 1s 1s Binding energy Fe 726~706eV 0542~527eV C294~279eV O,2eν Step: Fe 500m5/Step 0 200m5/Step C20m5/Step Data import of Tsupu Integration: Calculate the peak area 30 times; Set the linear background, take the area as the number of atoms, and calculate the area/(intake time/step)/correction factor (however, the correction factor is Fe 6.14.02.28,
C1,00 is adopted) Fe+O+C=100, and the percentage of each number of atoms is calculated.

Sampling method: 15x 10x2 mtn A)
Fill the container with toner and level it out.

In the present invention, any known carrier can be used as the carrier.

For example, iron powder, a resin-coated carrier, a carrier made of magnetic powder dispersed in resin, etc. can be used.

The magnetic toner and carrier described above are used as a two-component developer by mixing them in an appropriate ratio, and various additives can be added as necessary. Examples of these additives include charge control agents, cleaning aids, fluidity promoters, and the like.

On the other hand, as the electrophotographic photoreceptor, one made of an organic photo-S conductive material can be used. For example, photoconductive polymers such as poly-N-vinylcarbazole and low-molecular organic photoconductive polymers such as 2,5-bis-(p-diedylaminophenyl)-1,3,4-oxadiazole In addition, these organic photoconductive substances and various dyes,
A combination of pigments is used.

The image forming method of the present invention can be carried out by known means. The image forming method of the present invention will be explained with reference to the drawings. FIG. 1 is a schematic configuration diagram of an example of an electrophotographic copying apparatus embodying the present invention, in which 1 is a charger, 2 is an exposure means, 3 is a developing means, 4 is a transfer corotron, 5 is a static elimination corotron, 6 is a cleaner, 7 is an optical static eliminator, 8 is a recording paper, 9 is a fixing section, and 10 is a photosensitive drum.

A photoreceptor drum 10 having an organic photoconductive layer is rotating in the direction of the arrow. First, the surface of the photoreceptor drum 10 is uniformly charged by the charger 1 . Next, the exposure means 2 performs light irradiation according to the image information, and the photoreceptor drum 1 is exposed to light.
An electrostatic latent image is formed on the surface of 0. Note that any exposure means can be selected.

Next, the developing means 3 visualizes the electrostatic latent image using a two-component developer. At this time, the developing bias is appropriately selected depending on whether regular development or reversal image is performed.

The toner image is transferred onto the recording paper 8 by the transfer corotron 4, but may be transferred using means other than electrostatic transfer. The recording paper is then fixed in a fixing section 11. Further, the organic photoconductive layer of the photosensitive drum that has passed through the transfer section is treated with a static eliminator 5, a cleaner 6, and a photostatic eliminator 7 for reuse.
Cleaning is performed by

Example The present invention will be explained below with reference to Examples and Comparative Examples.

Example 1 Styrene/2-ethylhexyl acrylate (80/20) copolymer 100 parts Magnetic powder (EPT100O1 manufactured by Toda Kogyo 1) 20 parts carbon black (Regal 330, Cabot Hayashi I>io part Partial molecular weight Polypropylene Viscol 660p, Sanyo Made by Kasei ■ 5 parts Charge control agent (Bontron P-51, made by Orient Kagaku 11) 1 part The above ingredients were melted and kneaded in a Banbury mixer, and after cooling,
Fine pulverization was performed using a jet mill, and the finely pulverized product was further classified using a classifier to obtain a magnetic toner having an average particle size of 11 μs.

Example 2 Styrene/2-ethylhexyl acrylate (80/20) copolymer 100 parts Magnetic powder (81200, manufactured by Titan Kogyo ■) 20 parts carbon black (Regal 330, manufactured by Kabotsu 1~Run) 10 parts low force quantum polypropylene ( 5 parts Charge control agent (Bontron P-51, manufactured by Orient Chemical Co., Ltd.) 1 part The above ingredients were melted and kneaded using a Banbury mixer, cooled, and then finely ground using a jet mill. The finely pulverized product was further classified using a classifier to obtain a magnetic toner having an average particle size of 11.

Example 3 Styrene/2-ethylhexyl acrylate (80/20) copolymer 100 parts magnetic t
'[(EPTlooOlP Takogyo viJH> 3
083 carbon black (Regal 330, manufactured by Capot ■) io part partial molecular weight polypropylene viscol 660p, Sanyo Kasei (I Wooden) 5 parts Charge control agent (Positron P-51, manufactured by Orient Chemical ■) 1 part Add the above ingredients to a Banbury mixer After melting, kneading, and cooling, the mixture was pulverized using a jet mill, and the pulverized product was further classified using a classifier to obtain a magnetic toner having an average particle size of 11 μm.

Example 4 (comparative example) Styrene/2-ethylhexyl acrylate (80/20) copolymer 100 parts Carbon black (Recal 330, manufactured by Cabot U) 10 parts Low force molecular weight polypropylene (Viscol 660p, manufactured by Sanyo Kasei L.A.) 5 1 part Charge control agent (Bontron P-51, manufactured by Orient Chemical Co., Ltd.) 1 part The above ingredients were melted and kneaded in a Banbury mixer, and after cooling,
Fine pulverization was performed using a jet mill, and the finely pulverized product was further classified using a classifier to obtain a magnetic toner having an average particle size of 11N1.

Example 5 (comparative example) Styrene/2-ethylhexyl acrylate (80/20) copolymer 100 parts magnetic powder (B12O3, manufactured by Titanium Kogyo ■) 1 part carphone black (Recal 3301 manufactured by Cabot ■) 10 parts M
Polypropylene (Hiscol 660p, Sanyo Kasei (l wood) 5 parts Charge control agent (Bontron P-51, manufactured by Orient Chemical viJ) 1 part The above ingredients were melted, kneaded, cooled, and then jet milled. Fine pulverization was performed, and the finely pulverized product was classified using a classifier to obtain a magnetic toner having an average particle size of 11 μm.

Example 6 (comparative example) Styrene/2-ethylhexyl acrylate (80/20) copolymer iooo magnetic powder (EP 1000, Toda Igyo viJl> 1oo
Carbon black (Lee Cal 330, Cabot ■
10 parts low-molecular all-polypropylene (Viscol 660p, manufactured by Sanyo Kasei 11) 1 part charge control agent (Hontron P-51, Orient Chemical (1)) The above components were melted and kneaded in a Banbury mixer, and after cooling. ,
Fine pulverization was performed using a jet mill, and the finely pulverized product was further classified using a classifier to obtain a magnetic toner having an average particle size of 11 JiM.

As a carrier, ferrite powder 1 with an average particle size of 85 μm
00 parts to 1 part of styrene-maleic anhydride copolymer 15
A two-component developer was prepared by mixing the magnetic toners of Examples 1 to 6 above at a ratio such that the toner concentration was 3% by weight using a toluene solution coated with HO and using a vacuum kneader. .

When these two-component developers were used in a copying machine (XC1065, Xerox (I Wooden)) that uses an electrophotographic photoreceptor having an organic photoconductive layer, and a continuous copying test was conducted, the results are shown in Table 1. was gotten.

In the table, ○ indicates that there is little contamination inside the aircraft, and × indicates that there is significant contamination inside the aircraft.

Table 1

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an electrophotographic copying machine used to carry out the present invention. DESCRIPTION OF SYMBOLS 1... Charger, 2... Exposure means, 3... Developing means, 4... Transfer corotron, 5... Static elimination corotron,
6...Cleaner, 7...Photostatic eliminator, 8...Recording paper, 9...Fixing section, 10...Photosensitive drum. Effects of the Invention The image forming method of the present invention uses magnetic powder 3 as a magnetic toner.
Electrophotographic photosensitive material having an organic photoconductive layer is used because it contains ~30% of heavy metals and the exposed amount of the magnetic toner surface is 0.1% to 1.0% as iron element. When visualizing an electrostatic latent image formed on a body, it prevents surface contamination of the photoconductor by transfer materials such as paper and developer composition, prevents image loss, and prevents toner cloud formation. This has the effect of reducing in-flight contamination. Patent applicant Fuji Xerox Co., Ltd. Agent
Patent attorney Tsuyoshi Eyebe

Claims (1)

[Claims] (1) In an image forming method in which an electrostatic latent image formed on an electrophotographic photoreceptor having an organic photoconductive layer is developed using a two-component developer consisting of a carrier and a magnetic toner, a magnetic toner is used as the magnetic toner. An image forming method characterized by using a magnetic toner containing 3 to 30% by weight of powder and having an exposed amount of magnetic powder on the surface of the magnetic toner of 0.1 to 1.0% as iron element.