JPH041557Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a contamination prevention device for a corona discharger in a copying machine or the like.

(Prior Art) In a dry type copying machine, for example, a photosensitive drum provided with a photoconductive layer is charged with a first corona discharger to impart photosensitivity, and then exposed to a light image and charged with a second corona discharger. A known configuration is known in which an electrostatic latent image is created by being charged with different charges using a discharge device, then development and transfer are performed, and residual toner after transfer is cleaned by a cleaner before the next copying process begins. In such a configuration, dust such as toner scattered from the cleaner and developer and paper dust from the paper used as the transfer object floats in the air inside the machine.
In addition, during long-term continuous operation, the concentration of dust increases, and a high voltage current of approximately 6000 volts is applied to the corona discharger, so dust is attracted to the corona wire and corona house, and due to the adsorption of such dust, This caused uneven discharge, which eventually appeared as uneven copying.

For this reason, devices for preventing dust adsorption in corona dischargers have been seen, for example, as seen in Japanese Patent Publications No. 40-17229 and No. 42-16597, but in these devices, as shown in Figure 3, , air was introduced from the ceiling plate of the corona house of each corona discharger.

(Problem to be solved by the invention) However, the first step that imparts photosensitivity to the photosensitive drum 1 is
Since the corona discharger 2 and the second corona discharger 3, which is charged during exposure to a light beam image, are installed next to each other, air can be pumped into the corona house from the ceiling panel of the corona house as in the past. When the air is discharged from the opening facing the drum, the air flows out from the gap between the side of the corona house of each corona discharger and the drum, as shown in Figure 3, and the air flows out from the adjacent side facing each other. The problem was that the air flowing out from the sides collided with each other, creating a vortex, and as a result, some of the air flowed backwards and was again introduced into the corona house, bringing back dirty air. Furthermore, in order to feed air separately to each corona discharger, piping to constitute an air path is required, which has the disadvantage of complicating the structure.

The purpose of the present invention is to solve the above-mentioned problems of the prior art. Therefore, it is possible to drain out the dust in each adjacent corona discharger, prevent the backflow of the outflowing dust and bring it back, and to solve the problem in a simple manner. An object of the present invention is to provide a corona discharger antifouling device with a structure.

(Means for Solving the Problems) The feature of the corona discharger contamination prevention device according to the present invention is that a fan 10 is provided between a pair of corona dischargers 2 and 3 installed next to each other, and The fan is provided with a filter 11 on the suction side of the corona discharger, and the fan is provided with a filter 11 on the suction side of the corona discharger so that the air flow from the fan is guided by the side portions 22b and 32b of the pair of corona dischargers that face each other in close proximity. The drum is located further away from the ceiling board of the house.

(Function) In this contamination prevention device, since the fan 10 is located between the pair of corona dischargers, the air flow induced by the fan 10 is divided into approximately two halves, one of which is the corona discharger 2 and the photosensitive drum 1. The dust in the corona discharger 2 is sucked in together with the air inside the corona discharger 2 by the air flow and is discharged through the gap between the corona dischargers 2 and 2 in a direction opposite to the direction of rotation of the drum. Similarly, the other half of the airflow from the fan 10 flows through the gap between the other corona discharger 3 and the photosensitive drum 1 in the direction of rotation of the drum, thereby discharging dust within the corona discharger 3. Since the airflow generated by the fan 10 is divided into two parts and flows in opposite directions, the airflows do not collide with each other, and therefore no backflow occurs.

(Example) Next, an example of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the present invention, in which 1 is a photosensitive drum provided with a photoconductive layer, and a first layer is placed around the drum at an appropriate distance from the drum. A corona discharger 2 is installed, and a second corona discharger 3 is installed adjacent to and at a certain distance from the corona discharger 2.
Each corona discharger 2, 3 has a corona wire 2
1,31 and Corona House 22,3 surrounding it
Consists of 2. As shown in the figure, these corona houses are open on the side facing the photosensitive drum 1. In the illustrated example, the drum 1 is rotated clockwise, that is, in the direction of arrow A, and a cleaner 4 for cleaning residual toner is installed on the front side of the corona discharger 2 with respect to the rotation direction, and a cleaner 4 for cleaning residual toner is installed on the rear side of the corona discharger 3. A developing device 5 is arranged to visualize the electrostatic latent image. Therefore, the pair of corona dischargers 2 and 3 are arranged between the cleaner 4 and the developing device 5. In addition, a transfer device, a fixing device, etc. are arranged along the drum 1, but since they are not directly related to the present invention, illustrations and descriptions thereof will be omitted.

This contamination prevention device is composed of a fan 10 that sends airflow to a pair of adjacent corona dischargers 2 and 3, and a filter 11 that cleans the airflow. It is installed between electric appliances 2 and 3. fan 10
are attached to the casing plate 6 in the vicinity of these corona dischargers. The filter 11 is installed on the suction side of the fan 10, and is attached to the suction port defined by the casing 12 of the fan 10, as seen in FIG. Further, as shown in FIG. 2, the fan 10 is connected to the corona dischargers 2 and 3.
It is installed at approximately the center of the lengthwise direction.

As shown in FIG. 1, the fan 10 includes a ceiling plate 22a of the corona house 22, 32 of each corona discharger,
It is provided at a position farther from the photosensitive drum 1 than the fan 32a, and in this way, the airflow from the fan 10 can be dispersed in the longitudinal direction of the corona discharger, and
Guided by the closely facing sides 22b, 32b of each corona house 22, 32, the airflow reaches the drum 1 properly oriented, so that the airflow is an orderly flow. Since this air flow then heads toward the cleaner 4 and the developer 5 along the drum surface, it is possible to reliably prevent toner dust, etc. generated by these devices from entering the corona house.

During operation, air is purified and sucked through a filter 11 by a fan 1, and is blown onto the photosensitive drum 1 through a pair of corona dischargers 2 and 3, and the blown air flow is divided into two directions. As mentioned above, one side is the open side of the corona discharger 2 and the drum 1.
One flows in the direction opposite to the rotational direction of the drum 1 through the gap between the corona discharger 3 and the other in the rotational direction of the drum 1 through the gap between the opening side of the corona discharger 3 and the drum 1. The dust is expelled along with the air.

(Effect of the invention) As described above, according to the invention, the air containing dust in each corona discharger is sucked and discharged by the air flow passing through the gap between the opening side of the corona discharger and the photosensitive drum. Instead, part of the clean airflow that passes through the gap enters, so the dust discharged from the corona discharger does not return due to backflow, and the dust scattered outside by the airflow is removed from the corona discharger. Since entry into the interior of the generator is prevented, each adjacent corona discharger is always kept clean.
For example, if a fan was not installed, uneven copying would occur after 2000 to 3000 copies, but with this invention,
Even after copying over 30,000 copies, no unevenness occurred.
Furthermore, since the fan is provided between a pair of corona dischargers, there is no need for a duct or guide plate for guiding the air flow, and the structure is therefore extremely simple.

[Brief explanation of drawings]

FIG. 1 is an elevational view schematically showing a preferred embodiment of the dirt prevention device according to the present invention, FIG. 2 is a schematic plan view thereof, and FIG. 3 is an elevational view showing the prior art. In the figure, 1...photosensitive drum, 2, 3...corona discharger, 10...fan, 11...filter, 2
2a, 32a...Ceiling panels of Corona House.

Claims (1)

[Scope of utility model registration request] The corona discharger in a copying machine or the like includes a pair of corona dischargers provided around the photosensitive drum and adjacent to each other and located between a cleaner and a developing device provided around the photosensitive drum. The device for preventing contamination of electrical appliances includes a fan provided between the pair of corona dischargers and a filter provided on the suction side of the fan, and the airflow from the fan is directed between the pair of corona dischargers. 2. A contamination prevention device for a corona discharger, characterized in that said fan is located at a position farther from said drum than a ceiling plate of a corona house in said corona discharger so as to be guided by sides closely facing each other.