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AssigneePfu Limited
InventorsHironaga Hongawa, Satoshi Sakai, Eri Yamanashi, Isao Nagata, Shigeharu Okano, Yutaka Nakashima, Tadashi Nishikawa, Akihiko Inamoto, Satoshi Miyamoto
Estimating the term…
In the present invention, a toner image produced through a development process of supplying a liquid toner onto an image bearing body bearing an electrostatic latent image is transferred from the image bearing body onto an intermediate transfer body and then transferred from the intermediate transfer body onto a printing medium by use of a backup roller in a transfer-and-fixation zone. The printing medium is preheated to a temperature required for transfer and fixation before the printing medium reaches the transfer-and-fixation zone. No heating means is provided in the transfer-and-fixation zone, and the intermediate transfer body and the backup roller are pressed against each other at a high pressure ranging from 10 kg/cm2 to 60 kg/cm2. Alternatively, the intermediate transfer body is provided with heating means; resin for use in the liquid toner has a softening temperature not higher than withstand temperatures of members other than the intermediate transfer body such as a photosensitive drum; and the intermediate transfer body is heated to a temperature not lower than the softening temperature of the resin and not higher than the withstand temperatures of the other members.
A transfer-and-fixation system for a liquid-development electrophotographic apparatus, in which a toner image produced through a development process of supplying a liquid toner onto an image bearing body bearing an electrostatic latent image is transferred from the image bearing body onto an intermediate transfer body and then transferred from the intermediate transfer body onto a printing medium by use of a backup roller in a transfer-and-fixation zone,
A transfer-and-fixation system for a liquid-development electrophotographic apparatus, in which a toner image produced through a development process of supplying a liquid toner onto an image bearing body bearing an electrostatic latent image is transferred from the image bearing body onto an intermediate transfer body and then transferred from the intermediate transfer body onto a printing medium by use of a backup roller in a transfer-and-fixation zone,
Dependencies are inferred from the claim text.
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Of a toner pattern, e.g. a powder pattern , e.g. magnetic transfer: on a base other than paper
Using at least one intermediate support: with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent
Of a toner pattern, e.g. a powder pattern , e.g. magnetic transfer: with means for preconditioning the paper base before the transfer
Main transfer electrode: transfer drum
Term end not estimated
The present invention relates to a transfer-and-fixation system for a liquid-development electrophotographic apparatus for transferring a toner image from an intermediate transfer roller onto a printing medium and fixing the transferred toner image on the printing medium, by use of a backup roller.
In a liquid-development electrophotographic apparatus, a melt transfer system for fixing a toner image on a printing medium is desirably performed such that, when toner particles are to be brought into contact with the printing medium for transfer onto the medium, the toner particles and the medium have a temperature not lower than the melting temperature of toner particles. In the course of transfer, a backup force is applied to the back side of the medium so as to establish close contact between the toner particles and the medium, whereby the molten toner particles are transferred onto the medium by means of adhesion thereof.
Conventionally, as shown in FIG. 24, in a melt transfer-and-fixation system where toner is melted, and the molten toner is transferred onto and fixed on paper by means of adhesion thereof, in order to increase transfer efficiency and fixation strength, the temperature of a transfer roller and that of a backup roller must be set sufficiently high (e.g., 150° C.) in relation to the melting temperature of toner.
FIG. 1 is a view showing the overall configuration of an electrophotographic apparatus which uses a liquid toner and to which the present invention is applicable;
FIG. 2 is a view showing a first embodiment of a transfer-and-fixation system configuration to which the present invention is applicable;
FIG. 3 is a view for explaining that an image is thinned by surface tension;
Embodiments of the present invention will next be described in detail. FIG. 1 shows the schematic configuration of an electrophotographic apparatus which uses a liquid toner and to which the present invention is applicable. As illustrated, the electrophotographic apparatus includes, as main component members, a photosensitive body, a charger, an exposure unit, developing units corresponding to colors (only two developing units are illustrated), an intermediate transfer body IMR, and a backup roller.
The charger electrostatically charges the photosensitive body to about 800 V. The exposure unit exposes the photosensitive body to a laser beam having a wavelength of 780 nm, whereby an electrostatic latent image is formed on the photosensitive body such that an exposed portion of the photosensitive body assumes an electric potential of about 100 V.
The developing units are usually provided in correspondence with yellow, magenta, cyan, and black. The developing units are biased at about 400-600 V (E1) and form a toner layer having a thickness of about 5-10 μm on each of corresponding developing rollers by use of a liquid toner having a toner viscosity of 100-10000 mPa·S and a carrier viscosity of 50 cSt. The developing rollers supply positively charged toner particles to the photosensitive body according to respective electric fields established between the developing rollers and the photosensitive body, whereby the toner particles adhere to exposed portions (or unexposed portions) of the photosensitive body, which are electrostatically charged at about 100 V.