JPH0533161U - Corona charging device - Google Patents

Abstract

(57) [Summary] [Purpose] Maintain a stable discharge state even if the operating environment changes. [Constitution] Humidity is detected by a humidity detection sensor 3 installed near the discharge part. When the detected humidity is out of the predetermined reference range, a cleaning signal is sent from the comparison / determination means 2 to drive the cleaning means 5 to remove the dirt attached to the corona discharge wire 6.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a corona discharge device used in, for example, a copying machine or a laser printer, and more particularly to stabilization of corona discharge.

[0002]

[Prior Art]

 For example, when corona discharge is repeatedly performed in a corona charging device that charges the surface of a photoconductor such as a copying machine, foreign matter adheres to the corona discharge wire. When the amount of foreign matter attached increases, uneven discharge occurs, image quality deteriorates, and large vibrations occur in the corona discharge wire. If the corona discharge wire vibrates greatly, there is a danger of electric leakage. Therefore, it is necessary to remove the foreign matter attached to the corona discharge wire. In order to remove the foreign matter adhering to the corona discharge wire, the state of the corona discharge wire is changed according to the discharge current or power from the casing, which is the opposite electrode, as disclosed in Japanese Utility Model Laid-Open No. 60-46562. -Detected by up voltage and current, and when these detected values are above a certain value, the corona discharge wire is judged to be dirty and the corona discharge wire is cleaned.

[0003]

[Problems to be solved by the device]

 The state of corona discharge varies greatly depending on the environment in which it is used, and when used in a normal environment, even if the corona discharge wire is a little dirty, uneven discharge does not occur, but when the humidity is low or conversely high. Occasionally, even a small amount of dirt causes uneven discharge.

However, when the state of corona discharge is detected by a change in the discharge current of the casing, it can be detected only when the corona discharge wire is considerably dirty, and the occurrence of uneven discharge due to changes in the operating environment is prevented. I couldn't.

The present invention has been made in order to solve such a problem, and provides a corona charging device that can always maintain a stable discharge state by removing dirt on the corona discharge wire when the use environment changes. The purpose is to obtain.

[0006]

[Means for Solving the Problems]

 A corona charging device according to the present invention is a corona charging device having a corona discharge wire, a humidity detection sensor, a comparison / determination means, and a cleaning means, and the corona discharge wire performs corona discharge toward a charged body. The humidity detection sensor, which is installed close to and opposite to the body to be charged, detects the humidity inside the device, is installed near the discharge part, and the comparison / determination means determines the humidity inside the device based on a predetermined standard. It sends a cleaning signal when it is out of the range, is connected to the humidity detection sensor, and the cleaning means removes foreign matter adhering to the corona discharge wire, and receives the cleaning signal from the comparison and judgment means. It has a means for moving the corona discharge wire and a cleaning member.

Further, it is preferable that the comparison / determination means sends out a cleaning signal when the humidity in the apparatus becomes other than 40% to 70%.

[0008]

[Action]

 In the present invention, the humidity detection sensor installed in the vicinity of the discharge unit detects the humidity, and when the detected humidity exceeds the predetermined reference range, the cleaning signal is sent from the comparison and determination means to drive the cleaning means. Then, remove the dirt adhering to the corona discharge wire. A stable discharge state is always maintained by removing the dirt attached to the corona discharge wire when the detected humidity is outside the range of 40% to 70%.

[0009]

【Example】

 FIG. 1 is a block diagram showing an embodiment of this invention. As shown in the figure, the corona charging device has a charger 1, a DC high-voltage power supply device 2, a humidity detection sensor 3, a comparison judgment means 4 and a cleaning means 5. The charger 1 has a corona discharge wire 6 and a casing 7, and is installed near the surface of the photoconductor 8. The corona discharge wire 6 is for corona discharge toward the photoconductor 8 and is rotatably mounted in the end blocks 9 provided at both ends of the casing 7, as shown in the perspective view of FIG. It is wound around the pulley 10. A high-voltage applying unit 11 connected to the DC high-voltage power supply device 2 is connected to the one pulley 10. The casing 7 is a counter electrode for stabilizing the corona discharge of the corona discharge wire 6 and is connected to the ground.

The DC high-voltage power supply device 2 supplies a constant current high voltage to the corona discharge wire 6. The humidity detection sensor 3 is installed near the casing 7 and detects the humidity inside the apparatus. The comparison / determination means 4 is connected to the humidity detection sensor 3 and sends out a cleaning signal when the humidity detected by the humidity detection sensor 3 falls outside a predetermined reference range. The cleaning means 5 receives a cleaning signal from the comparison / determination means 4 and removes foreign matters adhering to the corona discharge wire 6, and the drive motor 12 and the end connected to one of the pulleys 10. It has a cleaning member 13 provided in the block 9 and having the corona discharge wire 6 sandwiched therein, as shown in the perspective view of FIG.

In describing the operation of the corona discharge device configured as described above, first, the relationship between the discharge state of the corona discharge wire 6 and the humidity will be described. When the corona discharge wire 6 is not dirty, the discharge state is not much affected by humidity, and even if the humidity changes, stable discharge is performed and discharge unevenness does not occur. However, if the corona discharge wire 6 gets dirty even a little, the discharge state is greatly affected by humidity, and as shown in the characteristic diagram of relative humidity and corona discharge state in Fig. 4, when the humidity is about 40% or less. , Discharge unevenness is apt to occur when it is above 70%.

Therefore, for example, a range of 40% to 70% in humidity is set as the reference value in the comparison determination means 4. Then, when corona discharge is being performed from the corona discharge wire 6, the humidity detecting sensor 3 detects the humidity in the vicinity of the charger 1 and sends the detected humidity to the comparing and judging means 4. The comparing and judging means 4 compares the sent humidity with a preset reference humidity range of 40% to 70%, and when the detected humidity is outside the reference humidity range of 40% to 70%, A cleaning signal is sent to the drive motor 12 of the cleaning means 5 for a predetermined time. The drive motor 12 is driven only during the time when the cleaning signal is received to rotate the directly connected pulley 10 to move the corona discharge wire 6 wound between the pair of pulleys 10. By the movement of the corona discharge wire 6, the surface of the corona discharge wire 6 is wiped by the cleaning member 13, and the dirt adhering to the surface is removed.

As described above, when the environment in which the charger 1 is used is too dry or the humidity is too much, the corona discharge wire 6 is immediately cleaned to remove the unevenness of discharge. It is possible to perform a stable discharge and form a high-quality image in a stable manner.

[0014]

[Effect of the device]

 As described above, this invention detects humidity with a humidity detection sensor installed near the discharge part and drives the cleaning means to drive the corona discharge when the detected humidity falls outside the predetermined reference range. Since the dirt attached to the wire is removed, it is possible to always perform stable discharge without uneven discharge.

Further, by removing the dirt adhering to the corona discharge wire when the detected humidity is other than 40% to 70%, it is possible to maintain a stable discharge state at any humidity. ..

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view showing the charger of the above embodiment.

FIG. 3 is a perspective view showing a cleaning member.

FIG. 4 is a characteristic diagram showing a relationship between relative humidity and a corona discharge state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging device 2 DC high-voltage power supply device 3 Humidity detection sensor 4 Comparison judgment means 5 Cleaning means 6 Corona discharge wire 8 Photoconductor 10 Pulley 12 Driving motor 13 Cleaning member

Claims (2)

[Scope of utility model registration request] 1. A corona charging device comprising a corona discharge wire, a humidity detecting sensor, a comparison / judgment means, and a cleaning means, wherein the corona discharge wire performs corona discharge toward a charged body. Is provided in close proximity to
The humidity detection sensor detects the humidity inside the device.
Installed in the vicinity of the discharge part, the comparison and determination means sends out a cleaning signal when the humidity inside the device is outside the predetermined reference range, is connected to the humidity detection sensor, and the cleaning means is a corona discharge wire. A corona charging device for removing adhered foreign matter, comprising: a cleaning member for moving a corona discharge wire in response to a cleaning signal from a comparison / determination means; and a cleaning member. 2. The comparing and judging means has a humidity in the device of 40% to 70%.
The corona charging device according to claim 1, wherein a cleaning signal is sent out when the value is other than%.