Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – To produce printing surface
Reexamination Certificate
2000-02-03
2001-06-26
Goodrow, John (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
To produce printing surface
C430S062000, C399S241000
Reexamination Certificate
active
06251552
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for developing an electrophotographic master plate for printing, and more particularly to a method of developing an electrophotographic master plate for printing having an insulating support member on which a conductive layer and a photoconductive layer are laminated and a developing apparatus for performing the developing method.
2. Description of the Related Art
A planographic printing plate for use in an electrophotographic method is manufactured by a wet electrophotographic plate making machine structured as disclosed in Unexamined Japanese Patent Publication (kokai) No. 10-260597. The outline of the foregoing machine will now be described. An electrophotographic master plate for printing (hereinafter simply abbreviated as a “master”) is conveyed to an electrifying portion to uniformly electrify the electrophotographic master plate for printing by virtue of corona discharge. Then, the electrophotographic master plate for printing is conveyed to an exposing portion to expose an image (an original document) to light. The master having the exposed image is conveyed to a developing apparatus also called a liquid-toner developing portion.
The wet electrophotographic developing apparatus is arranged to convey the master into toner developer enclosed between a pair of electrodes usually composed of a back plate (an electrode adjacent to a support member) and developing plate (an electrode adjacent to the surface which must be developed). Thus, toner development is performed in the toner developer. An example of a modification of the wet electrophotographic developing apparatus has been'disclosed in Unexamined Japanese Patent Publication (kokai) No. 9-96956. The foregoing apparatus is arranged to apply voltage to the pair of the electrodes during conveyance to form a toner image also using the foregoing function realized by the developer. The master incorporates a support member, such as paper to which conductivity has been imparted, and a photoconductive layer formed on the support member.
A portion of the masters incorporates the support member made of paper or the like and a photoconductive layer formed on the support member. The foregoing structure encounters irregularity in the density caused from states of tangling of pulp constituting the paper. Hence it follows that microscopic asperities are formed on the surface and, therefore, the flatness deteriorates. Moreover, permeability of coating solution encounters irregularity. Thus, the image quality deteriorates. Therefore, if the toner image is fixed as described above, improvement in the image quality has been limited.
To overcome the above-mentioned problems, it might be considered feasible to employ a resin sheet having flatness superior to that of the paper. The resin sheet, however, has no conductivity. Therefore, the resin sheet cannot be employed as the master which is developed by the electrophotographic developing apparatus.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a developing method and apparatus for wet-developing an electrophotographic master plate for printing which incorporates a resin sheet having an excellent electric insulating characteristic and satisfactory flatness.
(1) A method of developing an electrophotographic master plate for printing according to the present invnetion which incorporates an insulating support member, on which a conductive layer and a photoconductive layer are laminated, and electrode portions formed on the widthwise-directional side surfaces of said insulating support member and said photoconductive layer and arranged to electrically be connected to said conductive layer, said method of developing an electrophotographic master plate for printing comprising the step of: always electrically connecting said conductive layer to a conductive member through said electrode portions to ground said conductive layer during conveyance of said electrophotographic master plate for printing through a toner developer enclosed between a pair of electrodes disposed opposite to each other.
(2) An apparatus for developing an electrophotographic master plate for printing according to the present invention which incorporates an insulating support member, on which a conductive layer and a photoconductive layer are laminated, and electrode portions formed on the widthwise-directional side surfaces of said insulating support member and said photoconductive layer and arranged to electrically be connected to said conductive layer, said apparatus for developing an electrophotographic master plate for printing comprising: a conductive member which is previously grounded and is provided for a passage for conveying said electrophotographic master plate for printing to a toner developer enclosed between a pair of electrodes disposed opposite to each other, wherein said electrode portions and said conductive rollers are always brought into contact with each other during conveyance of said electrophotographic master plate for printing by conveying means so that said conductive layer is grounded.
(3) The apparatus for developing an electrophotographic master plate for printing according to (2), wherein said conductive member is conducitve rollers for conveying said electrophotographic master plate.
(4) The apparatus for developing an electrophotographic master plate for printing according to (2), wherein an electrode adjacent to said support member of said electrodes is previously grounded, and said electrode portions are brought into contact with said electrode adjacent to said support member during conveyance of said electrophotographic master plate for printing so that said conductive layer is grounded.
(5) The apparatus for developing an electrophotographic master plate for printing accorrding to (2), wherein said conductive member is a conductive brush.
(6) The apparatus for developing an electrophotographic master plate for printing accorrding to claim
2
, wherein said conductive member is at least one of a conductive roller, an electrode adjacent to said support member, and a conductive brush, which are previously grounded.
The electrophotographic master plate for printing according to the present invention incorporates the support member which has an electric insulating characteristic and on which the conductive layer and the photoconductive layer are formed. Moreover, the electrode portions which are electrically connected to the conductive layer are provided for the two widthwise directional ends. When the electrophotographic master plate for printing is developed, the conductive layer is grounded through the electrode portions as described in the aspect (1).
To ground the electrode portions, any one of the following members disclosed in aspects (2) to (6) may be employed: the rollers for conveying the electrophotographic master plate for printing; the electrode which is disposed adjacent to the support member and which is an electrode for applying voltage to the electrophotographic master plate for printing; and the conductive brushes disposed at the positions at which contact with the electrode portions is permitted.
When the electrophotographic master plate for printing is developed, the electrophotographic master plate for printing is conveyed into a developer enclosed between the pair of electrodes (the electrode adjacent to the support member and the electrode adjacent to the surface which is developed) disposed to sandwich the electrophotographic master plate for printing from the two surfaces of the electrophotographic master plate for printing. At this time, the electrode portions provided for the electrophotographic master plate for printing are inevitably brought into contact with at least any one of the rollers for conveying the electrophotographic master plate for printing, the electrode adjacent to the support member or the conductive brushes. Since at least any one of the rollers, the electrode adjacent to the support member and the cond
Kawamoto Chiaki
Nakayama Takao
Fuji Photo Film Co. , Ltd.
Goodrow John
Reed Smith LLP
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