JPH0481190B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates primarily to a charging position of an electronic copying machine used to charge a charged object such as a photoreceptor.

Conventional technology A corona charger is conventionally used as a charging position in electronic copying machines, but the corona charger uses a high-voltage power supply, which is dangerous, and also generates ozone when charging, which can cause damage to equipment. be.
Therefore, a charging position using a conductive brush is being developed as an alternative to the above-mentioned corona charger.
In conventional charging positions, the conductive brush of the charging roller is always in contact with the photoreceptor even when the charged object is stopped, resulting in problems such as the conductive brush becoming stale and charging characteristics deteriorating.

OBJECT OF THE INVENTION The present invention has been made for the purpose of eliminating such problems, and provides a charging position for an electronic copying machine that is retracted from the object to be charged when the charging roller stops, thereby preventing deterioration of charging characteristics. This is what we are trying to prevent.

Structure of the Invention At a charging position of an electronic copying machine, a charging roller is provided so as to be able to move toward and away from an object to be charged, and the charging roller is brought into contact with the object to be charged by utilizing centrifugal force generated as the charging roller rotates. In addition, since the conductive brush of the charging roller is separated by the object to be charged when copying is stopped, it is possible to greatly reduce sagging of the conductive brush.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings, in which 1 is an electronic copying machine (not shown).
A charged body 2 such as a photoreceptor is a charging roller installed below the charged body 1 and has a drive shaft 3 in a direction parallel to the axis of the charged body 1 . Both ends of the drive shaft 3 are supported by guide holes 4 formed in a frame, etc., and the drive shaft 3 is movable along the guide holes 4 to direct the charged object 1 toward and away from it. A total of four substantially dish-shaped rotating bodies 5, one pair on each side, are provided on both end sides of the rotating body 3 so as to face each other. Of these rotating bodies 5, the outer rotating body 5a is fixed to the drive shaft 3, and the inner rotating body 5b is attached to be movable in the axial direction of the drive shaft 3. A plurality of balls 6 are housed between them.

Further, between the end face of the core body 2b of the charging roller 2, which has a large number of conductive brushes 2a planted on the circumferential surface, and the rotating body 5b located inside, there is a compression spring 7 that biases the rotating body 5b outward. The back surface of the rotating body 5b, which is fitted into the drive shaft 3 and located inside, is in contact with the inclined surface 8a of the guide member 8, and is rotated by the centrifugal force acting on the ball 6. body 5
When b is moved in the direction of arrow a, the back surface of the rotating body 5b is guided by the inclined surface 8a, and the drive shaft 3 and charging roller 2 are configured to protrude toward the charged object 1 side.

Effects of the Invention Since the present invention has been described in detail above, when the drive shaft 3 starts rotating to charge the object 1 to be charged, centrifugal force is applied to the balls 6 interposed between the rotating bodies 5a and 5b. arrow a against the rotating body compression spring 7 provided movably with respect to the drive shaft 3.
Directed. As a result, the drive shaft 3
Since the charging roller 2 and the charging roller 2 are pushed out toward the charged object 1 side, the conductive brush 2a of the charging roller 2 comes into contact with the surface of the charged object 1 and charges it. Furthermore, when the copying is completed and the drive shaft 3 is stopped, the centrifugal force acting on the ball 6 also disappears.
The rotating body 5b is moved outward by the action of the compression spring 7, and as a result, the drive shaft 3 and the charging roller 2 are retracted in a direction away from the charged object 1 due to their own weight or biasing means, so that the charging roller The second conductive brush 2a moves away from the charged object 1 and stops. As a result, the amount of deformation of the conductive brush 2a, as shown by the broken line A in FIG. deterioration is also reduced. Furthermore, since the time that the conductive brush 2a is in contact with the charged object 1 is reduced, the wear of the conductive brush 2a is also reduced, and the life of the charging roller 2 is extended. Toner etc. adhere to the conductive brush 2a side, causing the conductive brush 2a to
The risk of the device becoming contaminated can be greatly reduced compared to conventional devices that are in constant contact with the device.

[Brief explanation of the drawing]

The drawings show a first embodiment of the invention, with FIG. 1 being a schematic diagram and FIG. 2 being a diagram showing the relationship between the number of copies and the amount of sagging. 1 is an object to be charged, 2 is a charging roller, and 2a is a conductive brush.

Claims (1)

[Claims] 1. In a device that charges the charged object 1 by bringing the conductive brush 2a into contact with the surface of the charged object 1,
The charging roller 2 having the conductive brush 2a is supported so as to be movable in the direction toward and away from the charged object 1, and the conductive brush 2a is supported by using the centrifugal force generated as the charging roller 2 rotates. A charging device for an electronic copying machine in which a charging roller 2 is advanced to a position where it comes into contact with a charged body 1.