Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Patent
1984-10-24
1987-02-03
Goodrow, John L.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
430122, 430137, 118657, G03G 914
Patent
active
046408800
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method of electrophotography and, more particularly, to a method of electrophotography in which an electrostatic latent image is developed with triboelectric magnetic toner with a chargeability by a magnetic brush method and in which the developed image is then transferred to a transfer member such as ordinary paper and is thereafter fixed to prepare a copy.
BACKGROUND OF THE INVENTION
The method of electrophotography prepares a copy by forming an electrostatic latent image on the photoconductive surface of a photosensitive member, by developing the electrostatic latent image to form a toner image, and by fixing the toner image either directly or after the toner image has been transferred to a transfer member. In case the electrostatic latent image is to be developed, a magnetic brush developing method is usually conducted, in which case a two-component system developer, which is a mixed powder comprising a non-magnetic toner and a carrier such as iron powder is used as a developing agent. When using this magnetic brush developing method with the two-component system developer, the carriers and the toner are mixed in a predetermined ratio and are frictionally charged so that the toner is charged with a predetermined polarity until it sticks to the surface where the electrostatic latent image is formed. Therefore, the magnetic brush developing method has the advantage that the transfer is feasible. However, the magnetic brush developing method requires means for mixing and frictionally charging the toner and the carriers to a satisfactory extent. Since only the toner is consumed during the development, moreover, the developing method requires the so-called "toner control device", i.e., a toner concentration monitoring device for maintaining a uniform toner concentration. As a result, the developing device needs to be bigger and have a more complicated construction. Moreover, since the carriers become exhausted after extended periods of time, the developing method has the problem that it is necessary to replace the carriers.
The developer, therefore, that has been used in recent years is a one-component system non-chargeable magnetic toner which is comprised essentially of magnetic powder and resin. A developing method using that magnetic toner, has been a method which is disclosed in Japanese Patent Publication No. 56-2705. The developing method disclosed selectively deposit toner on the surface of the electrostatic latent image by using as magnetic toner the conductive and magnetic toner which has an electric resistance of about 10.sup.4 to 10.sup.11 .OMEGA..multidot.cm when an electric field of a direct current of 100 V/cm is applied, by forming a magnetic toner carrier of a conductive sleeve, by electrically coupling the back of an electrostatic latent image carrier and the conductive sleeve thereby to form a electrically conductive path through the conductive and magnetic toner layer between the surface of the electrostatic latent image carrier and the conductive sleeve, by collecting at the leading end of a toner brush the charges which have a polarity opposite to that of the electrostatic latent image induced on the conductive sleeve by the charges of the electrostatic latent image, and by relatively moving the conductive sleeve and the electrostatic latent image carrier so that the coulomb force generated between the charges at the leading end of the toner brush and the charges of the electrostatic latent image may overcome the magnetic attraction generated by a permanent magnet roll disposed inside of the conductive sleeve.
The developing method thus disclosed can be applied to the so-called "CPC method", by which the toner image obtained by the development is fixed to directly prepare a copy, because the toner used has conductivity. However, the method intrinsically desired is not the aforementioned CPC method for a direct record but for an indirect record, i.e., the so-called "PPC method", by which a photosensitive member acting as a ma
REFERENCES:
patent: 4199356 (1980-04-01), Matsumoto et al.
patent: 4284702 (1981-08-01), Tabuchi et al.
patent: 4336318 (1982-06-01), Fukumoto et al.
Iimura Tsutomu
Kawanishi Tsuneaki
Mori Yasuki
Noguchi Koji
Goodrow John L.
Hitachi , Ltd.
Hitachi Metals Co., Ltd.
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