Electrophotography – Image formation – Development
Reexamination Certificate
2001-02-28
2003-01-28
Ngo, Hoang (Department: 2852)
Electrophotography
Image formation
Development
C399S233000, C399S237000, C015S256510
Reexamination Certificate
active
06512907
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a liquid electro-photographic device, and more particularly to a liquid electro-photographic device which performs multicolor image formation by providing plural sets of processing device of a liquid developing system therein and image outputs of printers, facsimiles, copiers and the like.
Conventionally, several kinds of systems are used in electro-photographic devices for outputting images of printers, facsimiles, copiers and the like by employing an electro-photographic technology. Among all, a liquid electro-photographic device called a tandem type providing plural sets of processing device of a liquid developing system therein is mostly used as a system for obtaining full-color images with high quality.
The electro-photographic device of the above-mentioned system forms a latent image by charging a surface of a photoconductor of a belt type or a drum type and writing a desired image using laser radiation. And the electro-photographic device develops the latent image by a liquid developer in a processing device. Usually, a full-color image is formed by four-color development providing four sets of processing devices.
A squeeze roller is provided in a processing device and pressed against the photoconductor for removing a residual liquid developer remaining on an image on the photoconductor immediately after a development and performing a conversion into films. The squeeze roller is cleaned when the electro-photographic device shifts to a standby state after finishing an image forming operation. The residual liquid developer still remaining after the cleaning is removed to the photoconductor and cleaned by a cleaning mechanism in the device.
In the above-mentioned prior art, in the event of a tandem type color liquid electro-photographic device, timing at which a second processing device rises (pressing against a photoconductor) is suspended while dirt is passing in the process of removing the dirt from a first processing device to the photoconductor with regard to a processing of a residual liquid developer on a squeeze roller placed in the processing device, when the device shifts to a standby state. In the event of the present sequence, a loss caused by a passing time is raised in the processing devices including a third and a fourth processing devices and a problem is caused that a shifting time for all of the processing devices to a standby state.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a liquid electro-photographic device capable of performing an operational sequence effectively including cleaning until a standby state of a processing device in the process of shifting from a printing operation to a standby state.
A liquid electro-photographic device of the present invention is a liquid electro-photographic device for forming a multicolor image by liquid processing a latent image on a photoconductor using plural processing devices, in which each of the above-mentioned processing devices has a developing roller for supplying a liquid developer to the above-mentioned photoconductor and a squeeze roller for performing removal of residual liquid developer from an image formed on the above-mentioned photoconductor and for forming an image into a film. And the liquid electro-photographic device is characterized in that the above-mentioned processing device is removed in order that the above-mentioned squeeze roller shifts from the state having a clearance from the above-mentioned photoconductor to the state being pressed against the above-mentioned photoconductor for performing a removal of the liquid developer remaining on the above-mentioned squeeze roller to the above-mentioned photoconductor in sequence when the image forming operation is finished after cleaning the liquid developer adhered on the above-mentioned squeeze roller and the removal proceeds sequentially from a processing device on a downstream side of a traveling direction of the above-mentioned photoconductor.
And the electro-photographic device of the present invention can be characterized in that the above-mentioned processing device is retracted in order that the above-mentioned squeeze roller shifts from the state having a clearance from the above-mentioned photoconductor to the state pressed against the above-mentioned photoconductor after performing the removal of the liquid developer remaining on the above-mentioned squeeze roller to the above-mentioned photoconductor in sequence and retraction proceeds sequentially from a processing device on a downstream side of a traveling direction of the above-mentioned photoconductor.
The electro-photographic device of the present invention can be characterized in that the processing device on a downstream side of a traveling direction of the above-mentioned photoconductor is retracted before the dirt of a liquid developer removed from a squeeze roller to a photoconductor of a processing device on an upstream side of the traveling direction reaches to the processing device on the downstream side.
The electro-photographic device of the present invention can be characterized in providing a squeeze blade for scraping a liquid developer adhered to the above-mentioned squeeze roller off.
The electro-photographic device of the present invention can be characterized in that when the image forming operation is finished, a pressure of the above-mentioned squeeze roller against the above-mentioned photoconductor is reduced to be less than the pressure during an image forming operation in order to clean the liquid developer adhered to the above-mentioned squeeze roller off and the above-mentioned squeeze roller is rotated in a reverse direction against the above-mentioned photoconductor. And the electro-photographic device of the present invention can be characterized in that after the above-mentioned squeeze roller is provided with a clearance to the above-mentioned squeeze blade, the above-mentioned squeeze blade contacts with the above-mentioned squeeze roller and the contact of the above-mentioned squeeze lade with the above-mentioned squeeze roller and the rotation of the above-mentioned squeeze roller are maintained for a certain period of time.
The electro-photographic device of the present invention can be characterized in setting a non-image area unavailable for an image forming in the above-mentioned photoconductor and performing a cleaning by rotating the above-mentioned squeeze roller in a reverse direction against the above-mentioned photoconductor in the above-mentioned non-image area.
The electro-photographic device of the present invention can be characterized in providing a squeeze cleaning roller for scraping the liquid developer adhered to the above-mentioned squeeze roller off.
The electro-photographic device of the present invention can be characterized in providing a cleaning blade for scraping the liquid developer adhered to the above-mentioned squeeze cleaning roller off.
The electro-photographic device of the present invention can be characterized in applying voltage to the above-mentioned developing roller, the above-mentioned squeeze roller and the above-mentioned squeeze cleaning roller, in which the voltage of the above-mentioned squeeze roller is set higher than the above-mentioned developing roller during the image forming operation and the voltage of the above-mentioned squeeze roller is set lower than the above-mentioned developing roller when the liquid developer adhered to the above-mentioned squeeze roller is cleaned off on finishing the image forming operation.
REFERENCES:
patent: 6321054 (2001-11-01), Park
Fuji 'Xerox Co., Ltd.
Ngo Hoang
Young & Thompson
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