Electrophotography – Internal machine environment – Forced air circulation
Reexamination Certificate
2000-11-28
2002-06-25
Brase, Sandra (Department: 2852)
Electrophotography
Internal machine environment
Forced air circulation
C399S098000, C399S397000
Reexamination Certificate
active
06411788
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying apparatus or a printer, and particularly to an image forming apparatus of a vertical feed type, wherein a sheet is fed in a vertical direction to pass the sheet through a transfer area.
Recently, as an image forming apparatus, a multiple apparatus (referred to as an MPF hereinafter) having functions as a copying apparatus, a facsimile, a printer and so on has been spreading.
As this MPF, there is known an in-body paper discharging type, wherein a sheet on which an image is formed is discharged inside the present apparatus in order to make the size of the apparatus small. In this in-body paper discharging type MPF, it is necessary to keep, inside the apparatus, a space for discharging sheets. Therefore, the sheets are fed in the vertical direction thereof to pass the sheets through the transfer area of the apparatus.
When in such vertical feed type MPFs a sheet that has passed through the transfer area is separated from its photosensitive drum, it is impossible that the sheet is laid down on a separation charger by gravity as in a conventional horizontal type. Therefore, there is a possibility that the feed pose of the sheet that has passed through the transfer area becomes instable so that inconveniences such as jamming are caused. For this reason, in conventional vertical feed type MPFs, air is sucked from the back side of their transfer charger and their separation charger to cause flow of the air near their transfer area, thereby adhering a sheet passing through the transfer area closely to the transfer charger and the separation charger. Thus, the feed pose of the sheet is made stable.
However, if airflow is caused inside an MPF as described above, toner that has leaked undesirably from its developing device and its cleaning device scatters inside the MPF. As a result, the following problems arise: its transfer charger and separation charger are polluted with the toner and the toner is discharged out of the apparatus. Particularly in both ends of the developing roller or both ends of the cleaning blade, from the viewpoint of structures thereof it is difficult that toner is completely sealed. Therefore, the amount of the toner leaking from these portions by the airflow caused in the apparatus increases undesirably, causing a problem that a great deal of the toner scatters inside the apparatus.
As a result, the toner adheres to the inside of the case of the transfer charger or the separation charger so that the electrical resistance of the portion to which the toner adheres increases. The amount of the electrical current flowing in the photosensitive drum increases accordingly. Alternatively, leakage is caused at the portion of the case to which no toner adheres. Such problems arise. When the amount of the electrical current flowing in the photosensitive drum increases, excessive transfer or excessive separation is caused to generate image failures such as a pockmark. When the leakage is caused inside the case of the transfer charger or the separation charger, the MPF may operate erroneously.
BRIEF SUMMARY OF THE INVENTION
In light of the above-mentioned situations, an object of the present invention is to provide an image forming apparatus making it possible to stabilize the feed pose of a transferring material and suppress the amount of a scattered developer in the apparatus.
To attain the above-mentioned object, the image forming apparatus of the present invention comprises: a developing device for supplying a developer to a latent image formed onto an image carrying body to develop the latent image; a feeding device for feeding a transfer material, using a feed path extending along the image carrying body; a transferring device for transferring the developer image developed by the developing device onto the transfer material fed using the feed path; an airflow forming device for forming flow of air for stabilizing feed pose of the transfer material that has passed through a transfer area between the transferring device and the image carrying body; and a regulating member for regulating a part of the airflow formed by the airflow forming device.
The image forming apparatus of the present invention comprises: a developing device comprising a developing roller that can contact an image carrying body, for causing the developing roller to be rotated so as to supply a developer to a latent image formed onto the image carrying body, thereby developing the latent image; a feeding device for feeding a transfer material, using a feed path extending along the image carrying body; a transferring device for transferring the developer image developed by the developing device onto the transfer material fed using the feed path; a separation device for separating, from the image carrying body, the transfer material on which the developed image is transferred by the transferring device; an airflow forming device for sucking air from the side, opposite to the image carrying body, of the feed path to form flow of air advancing from the image carrying body to the transferring device and the separation device, to adsorb the transfer material passing through a transfer area between the transferring device and the image carrying body, thereby stabilizing feed pose of the transfer material; a cleaning device for cleaning the developer remaining on the image carrying body without being transferred by the transferring device; and a regulating member for regulating a part of the airflow formed by the airflow forming device.
The image forming process of the present invention comprises the steps of: rotating a developing roller that contacts an image carrying body to supply a developer to a latent image formed onto the image carrying body, thereby developing the latent image; feeding a transfer material to the developer image developed on the image carrying body; transferring the developer image onto the fed transfer material; forming flow of air for stabilizing feed pose of the transfer material on which the developer image is transferred; and regulating a part of the airflow to reduce a scattered amount of the developer.
The image forming process of the present invention comprises the steps of: rotating a developing roller that contacts an image carrying body to supply a developer to a latent image formed onto the image carrying body, thereby developing the latent image; feeding a transfer material to the developer image developed on the image carrying body; transferring the developer image onto the fed transfer material; forming flow of air for stabilizing feed pose of the transfer material on which the developer image is transferred; and regulating a part of air passing through the vicinity of both ends in the axial direction of the developing roller, among the above-mentioned airflow, to reduce a scattered amount of the developer.
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patent: 1-28513 (1989-08-01), None
Brase Sandra
Foley & Lardner
Toshiba Tec Kabushiki Kaisha
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