Cleaning Device for Copying Machines

The present invention relates to an improved cleaning device that collects residual toner from the photoconductive surface of an electrophotographic copying machine by using a rotary brush before the collected toner is eventually deposited in a specific part such as a filter via vacuum means.

Conventionally, there are a variety of methods used for such a cleaning device that collect residual toner from the photoconductive surface. Of these, cleaning by a brush is most widely employed, since it effectively and stably achieves the desired cleaning effect, thus meeting the need for faster copying services.

FIG. 1 shows a typical configuration of a conventional copying machine employing the above-mentioned cleaning device using a brush, in which, corona discharger 2, developer brush 3, transfer corona discharger 4, discharged corona discharger 5, cleaner unit 6, and a discharge lamp 7, are respectively provided around the photoconductive surface 1 at proper intervals. A latent image is formed on the photoconductive surface 1 by charged corona discharger 2 and an exposure light 8 is developed by developer brush 3 before being transferred onto a copying paper by the transfer corona discharger 4. After a transfer operation is completed, residual toner is then removed from the photoconductive surface 1 by the corona discharger 5 and cleaner 6 before being sent to filter 9. Such a cleaner 6 includes a cleaning brush 60 and a scraper that scrapes residual toner from the surface of the brush 60. Filter 9 is provided with a filter bag 90 containing an air filter that collects toner from the cleaner for deposit. A vacuum unit 10 absorbs the removed toner from the cleaner 6 into filter 9 and is provided above the filter 9.

As described above, such a conventional cleaning device includes the said cleaner 6 that wipes the residual toner from the photoconductive surface 1, filter 9 collecting the removed toner, and a vacuum unit 10 behind the vacuum passage used for collecting the removed toner. However, since these devices are located behind the vacuum passage, i.e., behind the filter unit, quite a powerful vacuum force is needed to effectively collect the removed toner, and thus, relatively great vacuum capacity should be provided. In addition, due to the increased vacuum capacity, an AC motor should also be provided, thus unavoidably requiring a larger space, while generating unwanted noise and causing relatively large amounts power to be dissipated.

It is an object of the present invention to provide a cleaning device that effectively minimizes noise and power consumption and also achieves a compact configuration of the entire unit by providing a vacuum unit in front of a specific part of the unit that collects the residual toner.

A preferred embodiment of the present invention provides a cleaning device that collects the residual toner from the photoconductive surface of a copying machine by using a rotary brush and then deposits the collected toner in a specific part, via vacuum means, in which it provides an air duct between the specific part and rotary brush, and in addition, it provides a vacuum fan in a proper position inside the air duct. As described above, a preferred embodiment of the present invention provides an air duct between a specific toner deposit part such as a filter bag and a rotary brush, while the vacuum fan provided in a proper position inside the air duct minimizes loss of the absorbing vacuum force, and as a result, an extremely compact fan motor can be used, while noise and power consumption are minimized. In addition, such a configuration makes it possible to construct a copying machine at a low cost with simple construction without containing a filter bag cover that is otherwise needed for any of the conventional devices.

FIG. 1 is a simplified block diagram of a conventional copying machine containing a conventional cleaning device; and

FIG. 2 is a simplified block diagram of a cleaning device as a preferred embodiment of the present invention.

FIG. 2 is a simplified block diagram of a cleaning device as a preferred embodiment of the present invention. The cleaning device of FIG. 2 includes a configuration that is entirely different from any of the conventional cleaning devices typically shown in FIG. 1. The cleaning device in the preferred embodiment of the present invention typically incorporates an air duct 11 connected between an opening 62 behind the cleaner and the other opening 90a of filter bag 90 that deposits the removed toner, and a vacuum-activating propeller fan 12 in the center part of the air duct. The center part of air duct 11 is composed of sleeves 11a to which said propeller fan 12 is secured.

Residual toner removed from the photoconductive surface 1 by both the rotary brush 60 and scraper 61 is first attracted by a vacuum developed by propeller fan 12 before being sent to the filter bag 90 via an air duct 11 and the propeller fan 12. Since the filter bag 90 is composed of an air filter as with the one shown in FIG. 1, only the collected toner is deposited inside the air filter, while air is exhausted outside. In order to prevent the bearing part of said fan motor from being clogged by the vacuumed toner containing several ten microns of fine particles, the bearing part of the fan motor should desirably be sealed. Likewise, in order to prevent portions adjacent to the motor from being heated, for example the image transfer glass, air duct 11 including sleeve 11a should be desirably be composed of such a material having satisfactory heat radiation effects. Since the vacuum activating propeller fan 12 is provided in a proper position inside the air duct, the cleaning device embodied by the present invention makes it possible to set both the propeller fan 12 and cleaner 6 at a distance close to each other as compared to that shown in FIG. 1, and as a result, the propeller fan 12 can apply its vacuum force directly to the cleaner 6, thus minimizing loss. In addition, since the air to be externally discharged from the filter bag 90 may be released to any areas where no problems arise, such a filter bag cover (reference 91 shown in FIG. 1) which is otherwise needed for any of the conventional units can be eliminated.