JPH0542437Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Use The present invention relates to a charging device that charges and neutralizes a photoreceptor of a copying machine.

Prior Art As shown in FIG. 3, plastic blocks 2 are provided at both ends of a metal shield 1, and a wire 3 is fixed to the blocks 2 with screws 4 and stretched in the longitudinal direction of the shield 1. A charging device called a corotron is known in which a high voltage is applied to the wire 3 from a connector 5 provided on the block 2 to cause discharge.

Problems that the invention aims to solve: Since the metal shields 1 are located on both sides of the block 2, high voltage current is transmitted across the surface of the block 2 from the live part, that is, the screw 4 that fixes the wire 3 to the block 2. The voltage applied to the wire 3 may decrease due to leakage, and the photoreceptor may not be able to be charged or neutralized without being discharged, resulting in no image being produced.

Also, due to leakage, the surface of the block becomes carbonized, and once carbonized, electricity escapes from that part and the voltage does not increase, making it unusable as a charging device. In severe cases, the carbonized part may catch fire. There were safety problems, such as the paper passing through the top of the shield 1 burning due to the leaked current.

In addition, since the discharge suddenly starts from the wire 3 portion away from the block 2, the discharge distribution of the discharge current in the axial direction of the charging device is overshot at both axial ends of the charging device, as shown by the dotted line in Figure 4. A peak value occurs, and the surface of the photoreceptor cannot be uniformly charged or neutralized, and the surface of the photoreceptor is likely to attract dust, toner, etc. and get dirty, and the dirt may cause leakage.

Since both ends of the shield 1 are closed by the blocks 2, dirt and the like inside the shield 1 cannot be exposed.

Means and Effects for Solving the Problems As shown in FIGS. 1 and 2, the present invention provides plate-shaped mounting pieces that are narrower than the bottom wall on both longitudinal end surfaces of the bottom wall of the shield. The shield is provided so as to protrude in the longitudinal direction from both ends in the longitudinal direction of both side walls of the shield, and a block is provided on this mounting piece at a distance from both ends in the longitudinal direction of the both walls of the shield, and a wire is fixed to this block to secure the block. Both side walls of the shield are not located on both sides, and both longitudinal ends of the shield are open.

Example A metal shield 10 has a bottom wall 11 and both side walls 1
2 and 12, it becomes a long material with a U-shaped cross section,
A bottom wall 1 is provided on both longitudinal end surfaces 11a of the bottom wall 11.
A plate-shaped mounting piece 13 narrower than 1 is attached to both side walls 12,
A plastic block 14 is integrally formed on the mounting piece 13 so as to protrude in the longitudinal direction from both ends of the shield 10 in the longitudinal direction.
A wire 15 is fixed to the upper surface of the block 14 with a bolt 16.

The block 14 is a rectangular parallelepiped that is wider than the mounting piece 13 and is spaced apart from the end of the shield 10.

Effect of the invention: Both side walls 1 of the shield 10 are placed on both sides of the block 14.
Since blocks 2 and 12 are not located, that block 1
As the distance between the live part of block 14 and both side walls 12, 12 of shield 10 becomes longer, high voltage current flows from the live part of block 14 along the surface of block 14 to shield 1.
Leakage to the side walls 12, 12 of the wire 15 is reduced, the voltage applied to the wire 15 is not lowered and no discharge occurs, and the block 14 is less likely to be damaged by leakage, improving durability. .

Further, the block 14 is connected to both side walls 1 of the shield 10.
2 and 12 are separated in the longitudinal direction, the discharge distribution has a flat rise as shown by the solid line in Figure 4, and no peak value occurs as in the conventional case, so the surface of the photoreceptor can be uniformly charged and neutralized. At the same time, it becomes difficult for dirt, toner, etc. to be attracted to both ends of the charging device in the axial direction, and the charging device becomes less likely to get dirty, making it difficult for cliques to occur due to dirt.

Further, since the side walls 12, 12 of the shield 10 and the block 14 are separated from each other in the longitudinal direction, both ends of the shield 10 in the longitudinal direction are open, and the mounting piece 13 is in the form of a plate narrower than the bottom wall 11. Because of this, when removing dirt from the shield 10, block 1
4. Dirt inside the shield 10 can be easily removed without the attachment piece 13 getting in the way.

In other words, since the inside of the shield 10 becomes very dirty due to discharge, it is necessary to periodically clean the inside of the shield 10, and this cleaning work becomes easier.

Further, by providing the block 14 on the mounting piece 13, the block 14 can be attached to both side walls 12, 1 of the shield 10.
Since the distance between the live part of the block 14 and both side walls 12, 12 of the shield 10 is increased, the dimension between the side walls 12, 12 of the shield 10, that is, Since the width of the shield 10 can be the same as the conventional one and the width of the charging device does not become particularly large, it is preferable as a charging device disposed around the photoreceptor.

That is, in addition to the charging device, components such as a developing machine and a cleaner are disposed around the photoreceptor;
Since a plurality of charging devices are provided, it is not preferable in terms of space if the width of the charging device becomes large.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a plan view showing an embodiment of the present invention, FIG. 3 is a perspective view of a conventional example, and FIG. 4 is a table showing discharge distribution. 10 is a shield, 13 is a mounting piece, 14 is a block, and 15 is a wire.

Claims (1)

[Claims for Utility Model Registration] The bottom wall 11 is made of a long material having a substantially U-shaped cross section with both side walls 12 erected from both sides of the bottom wall 11 in the longitudinal direction; A metal shield 10 having plate-shaped mounting pieces 13 narrower than the bottom wall 11 on both longitudinal end faces 11a of a wall 11 and protruding in the longitudinal direction from both longitudinal ends of the side walls 12, 12. and both side walls 1 of the shield 10 are placed on the mounting piece 13.
1. A charging device comprising: a block 14 provided longitudinally apart from the longitudinal ends of the wires 2 and 12; and a wire 15 fixed across the surfaces of the block 14.