Patent Application
20050074256
A. Field of the Invention
The invention relates generally to image forming devices, and more particularly to a method and apparatus for removing contaminants from an electrode in an image forming device using a polishing agent.
B. Background of the Invention
Electrodes for charging a photosensitive body to a prescribed potential in image forming devices such as photocopiers, facsimile machines, and laser printers are known. Over time, these electrodes become contaminated with residual toner, dust, etc., and thus require regular cleaning. As such, cleaning members have been proposed for cleaning contaminated electrodes as part of image forming devices and the like that include such electrodes. However, a need still exists for low cost cleaning members and cleaning members that remove a greater amount of contaminates.
According to one embodiment of the present invention, an image forming device is provided with a photosensitive body which applies a toner on a media, an electrode which charges the photosensitive body to a prescribed potential, and a cleaning member which removes contaminants from the electrode using a polishing agent. The cleaning member preferably includes an inner region having a first amount of the polishing agent, and an outer region radially outward from the inner region and having a second amount of the polishing agent, wherein the first amount is less than the second amount.
According to another embodiment of the present invention, a method of cleaning an electrode in an image forming device is provided, the electrode including a plate having a sawtoothed-shaped tip. The method includes steps of moving a cleaning member substantially parallel to a plane of the plate, compressing the cleaning member with the sawtoothed-shaped tip, and removing contaminants from the sawtoothed-shaped tip using a polishing agent via contact between the cleaning member and the sawtoothed-shaped tip. Preferably, the cleaning member includes an inner region having a first amount of the polishing agent, and an outer region radially outward from the inner region and having a second amount of the polishing agent, wherein the first amount is less than the second amount.
According to another embodiment of the present invention, an image forming device is provided with means for applying a toner on a media, means for applying a prescribed charge on the means for applying a toner on a media, and means for cleaning the means for applying a prescribed charge. The means for cleaning preferably has a higher concentration of polishing agent in an outer region than in an inner region of the means for cleaning.
Further features, aspects and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying drawing figures.
Reference will now be made in detail to presently preferred embodiments of the invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
An image forming unit useable with various embodiments of the present invention is shown in the block diagram of
An exemplary charging device 120 according to another embodiment of the present invention is shown in greater detail in the block diagram of
Additionally, as part of the charging device 120 or as a separate component, a cleaning member 500 (e.g., an elastic foam roller) is provided for removing contaminants 501 from the electrode plate 200 (see
As shown in the side view of
To further improve the cleaning performance of the cleaning member 500, a polishing agent is provided, such as a resin including one or more of silicon carbide, silicon nitride, cerium oxide, iron oxide, chromium oxide, and alumina particles. Preferable, the polishing agent particles have an average particle diameter in the range of about 0.01 to about 2 microns, more preferably in the range of about 0.01 to about 1 microns.
Additionally, the amount of polishing agent in the inner region 510 and the outer region 520 is different, such that the inner region 510 has a smaller amount of polishing agent than the outer region 520. By way of example, the inner region 510 may have little or substantially no polishing agent, and the outer region 510 may have an amount of polishing agent ranging from about 0.01% to about 5% by weight. Furthermore, the amount of polishing agent in inner region 510 and/or outer region 520 may be substantially uniform throughout a given layer as shown in
A table comparing conventional cleaning techniques to various embodiments of the present invention using a polishing agent in cleaning member 500 is provided below for illustration purposes. In particular, the following table is provided in reference to a cleaning technique described in Japanese Reference 9-211940 to Nakakama, which is incorporated by reference herein in its entirety.
X: Unevenness appears on a white media (white media being the media on which an image is formed).
Z: Unevenness appears in have-tone mode on a white media.
◯: Substantially no unevenness appears on a white media.
As can be seen from the table provided above, the cleaning member 500 according to various embodiments of the present invention provides a greater degree of cleaning over conventional cleaning techniques using the same charging device 120, particularly with amperages of 600 μA or less being used for the charging device 120 (the current being applied during an image forming process). Hence, the present invention reduces the appearance of uneven images, reduces contaminate related damaging of electrode plate 200, and other problems associated with inadequate cleaning of the charging device 120. Other advantages will also be realized by practicing various embodiments of the present invention, as would be readily apparent to one of ordinary skill in the art after reading this disclosure.
The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light in the above teachings or may be acquired from practice of the invention. The aspects of the embodiments may be combined with one another. The embodiments were chosen and described in order to explain the principles of the invention and a practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications are suited to the particular use contemplated.
