JP2544147Y2 - Corona discharge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a corona discharge device used in an electrophotographic apparatus such as a copying machine and a printer.

[Prior Art] FIG. 4 shows an example of a conventionally known electrophotographic apparatus. Reference numeral 1 denotes a rotatable photosensitive drum having a photosensitive member capable of forming an electrostatic latent image on its outer peripheral surface. doing. The photosensitive drum 1 is connected to a driving device (not shown) and rotates in a direction indicated by an arrow A during printing. Around the photosensitive drum 1, a corona discharge device 2, an image exposure device 3, a developing device 4, a transfer corona discharge device 5, an AC separation corona discharge device 6, and a cleaning device 7 having a known configuration are sequentially and operatively arranged. The discharging device 2, the image exposing device 3, and the developing device 4 form a toner image on the surface of the photosensitive drum 1 according to the document information. This toner image is transferred onto the transfer material conveyed from the paper supply unit 8 by the action of the transfer corona discharge device 5. The transfer material after the transfer is separated from the surface of the photosensitive drum by the action of the AC separation corona discharge device 6, and the belt device 11
To the fixing device.

The corona discharge device used for image formation, transfer, and separation as described above includes a box-shaped housing that extends in the axial direction of the photosensitive drum 1 close to the peripheral surface of the photosensitive drum 1, and a housing inside the housing. The housing has a corona wire electrode stretched in the longitudinal direction, the housing is open on the side facing the photosensitive drum (hereinafter referred to as the upper side), and the lower wall (the side remote from the photosensitive drum) is closed.

On the other hand, in order to remove ozone generated by the corona discharge and dust floating in the corona discharge device, an opening is formed in the lower wall of the housing so as to extend in the longitudinal direction over substantially the entire length or a considerable length. A configuration has been proposed in which the inside of the discharge device is suctioned with air by a suction device such as a fan or a blower through an opening.

[Problem to be Solved by the Invention] When the opening is formed in the lower wall of the housing over a considerable length, particularly in a long corona discharge device for copying a large-sized image, use of the device is difficult. During operation, both side walls vibrate due to vibration from other driving parts, etc., and the distance between both side walls becomes uneven along the longitudinal direction,
As a result, uneven corona discharge occurs.

It is an object of the present invention to provide a corona discharge device having an opening as described above, which has a simple configuration and can provide a uniform corona discharge even in a long size for a large size. And

[Means for Solving the Problems] In order to solve such problems, the present invention provides an upper portion having both side walls facing each other with a gap therebetween and having a single opening in a lower wall extending in a direction in which the side walls extend. In a corona discharge device having a U-shaped cross-sectionally open housing and a corona wire electrode provided in the housing so as to extend in the extending direction, the corona discharge device is provided at a plurality of locations along the extending direction of the housing. It has a plurality of electrically insulating vibration preventing members provided so as to straddle the opening in the lower wall, and these vibration preventing members have their ends separated from the corona wire electrode at a position farther from the corona wire electrode than the opening in the lower wall. It is characterized by being fixed to a wall.

Preferably, the vibration preventing member is fixed to the lower wall by fusion.

[Operation] By the above-described means, the vibration preventing members fixed to the plurality of locations of the lower wall always work to keep the width of the opening formed in the lower wall at a predetermined value, thereby making it possible to use the conventional apparatus when using it. To prevent vibration of both side walls. In addition, since the vibration preventing member is made of an electrically insulating material, it is possible to prevent the occurrence of uneven discharge between a portion where the vibration preventing member is provided and the opening, and to perform even charging. That is, the discharge from the corona wire goes to the vibration preventing member instantaneously, but since the vibration preventing member is instantaneously charged and becomes saturated, the subsequent discharge does not go to the vibration preventing member, and As in the case of the discharge of the photoconductor, it goes to the side wall of the housing and the surface of the photoconductor. As described above, despite the existence of the vibration preventing member, the electrical interference between the portion having the vibration preventing member and the opening portion can be substantially ignored, and does not substantially adversely affect the corona discharge.

Hereinafter, the present invention will be described with reference to the drawings.

1 to 3 show an example in which the present invention is applied to a transfer corona discharge device. The transfer corona discharge device 21 is AC in this example.
It has a housing 20 that is provided integrally with the separated corona discharge device 22 and that is open at the top. The housing 20 is fixed to the upper surface of a rail 23 extending in the axial direction of the photosensitive drum 1 and having a U-shaped cross section. The rail 23 is moved along a rail guide (not shown) provided in the electrophotographic apparatus. The housing 20 is inserted from the axial side of
Are arranged at predetermined positions with respect to the surface of the photosensitive drum.
The rail 23 is provided on its upper wall with openings 29 and 30 extending along the longitudinal direction of the rail, and these openings are communicated with a duct 53, as shown in FIG. The inside of the housing is suctioned through the opening by the action of a suction device such as a fan or a blower. rail
End members 24 and 25 made of an electrically insulating material constituting a part of the housing 20 are fixed to each of both ends in the longitudinal direction of the housing 23 by screws or the like. A handle 26 used to pull out the housing from the electrophotographic apparatus along the rail guide is formed on one end member 24, and the housing is mounted on the predetermined position on the other end member 25. Sometimes it is connected to a suitable socket,
Terminals 27 and 28 are provided for electrically connecting the corona wires stretched within the housing to the appropriate DC and AC power supplies through the socket.

A conductive housing member 31 having a U-shaped cross section is fixed to the end members 24 and 25 by a suitable means such as screws or caulking so as to surround one opening 29 of the rail 23. The housing member 31 forms a housing of the transfer corona discharge device 21. The housing member 31 is spaced apart and faces the side wall.
32 and 33, and the side walls 32 and 33 extend substantially parallel to the axial direction of the photosensitive drum 1. The lower wall of the housing member 31 has an opening 34 extending in the direction in which the side walls 32 and 33 extend.
Is formed, and the housing member 31 is arranged such that the opening 34 overlaps with the opening 29 of the rail 23.

As described above, in a housing having such an opening, the side wall vibrates during use, causing non-uniform corona discharge.

Reference numeral 41 denotes a vibration preventing member made of an electrically insulating material, for example, a synthetic resin such as Duracon. In this example, the vibration preventing member 41 is formed of a triangular thin plate whose center is hollowed out, and includes a lower wall of the housing member 31 and a pin portion 41a integrally provided so as to protrude downward at the lower surface of each corner. A pin portion that is inserted into a through hole formed in alignment with the upper wall of the rail 23 and protrudes from the lower surface of the rail 23
By fusing the tip portion of 41a by heat, the vibration preventing member 41 is fixed to the housing member 31 and the rail 23.

Reference numeral 36 denotes a second housing member, which cooperates with a side wall 33 of the housing member 31 of the transfer corona discharge device to constitute a housing of the separated corona discharge device 22. Housing member
Reference numeral 36 extends in the axial direction of the photosensitive drum 1, and its lower wall is brought into contact with the upper surface of the rail 23 at a position so as not to block the opening 30 of the rail, and both ends in the longitudinal direction are connected to the end members 24 and 25. It is provided detachably by a screw 38. By removing the screw 38 and removing the housing member 36,
The inside of the separation corona discharge device is exposed, so that the inside can be easily cleaned. Reference numerals 51 and 52
Indicates a corona wire electrode.

The vibration member 41 is not limited to a triangular shape as in the above example,
Any shape may be used as long as it is fixed to the lower wall of the housing member 31 on each side across the opening 29 of the housing member 31,
Preferably, the configuration is such that it is fixed at three or more points.

Although the transfer corona discharge device has been described in the above example, the present invention can be applied to other corona discharge devices such as a corona discharge device for image formation or a separated corona discharge device.

[Effects of the Invention] As described above, according to the present invention, it is possible to perform corona discharge without vibration due to vibration without substantially affecting the corona charging characteristics.

[Brief description of the drawings]

1 is a top view of the corona discharge device according to the present invention, FIG. 2 is a side sectional view of the corona discharge device of FIG. 1, and FIG. 3 is a part of an electrophotographic device incorporating the corona discharge device of FIG. FIG. 4 is a schematic side sectional view showing an example of an electrophotographic apparatus. 20 ... housing, 21 ... transfer corona discharge device, 22 ... separation corona discharge device, 31, 36 ... housing member, 32, 33 ... side wall, 29, 30, 34 ... opening, 41 ... vibration prevention member.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-50085 (JP, A) JP-A-57-172363 (JP, A) JP-A-52-18335 (JP, A) JP-A 54-85 92753 (JP, A) Fully open 1983-143644 (JP, U) Fully open 60-118151 (JP, U) Fully open 58-59051 (JP, U) Fully open 56-66954 (JP, U) Tokiko 47-34346 (JP, B1)

Claims (2)

(57) [Scope of request for utility model registration] 1. A housing having a U-shaped cross section which has an open upper side and has a single opening extending in a direction in which the side wall extends, the housing having both side walls facing each other with a space therebetween, and inside the housing. In a corona discharge device having a corona wire electrode extending in the extending direction, a plurality of electrical insulators provided so as to straddle an opening of the lower wall at a plurality of locations along the extending direction of the housing. A corona discharge device comprising: a vibration-preventing member having an end portion fixed to the lower wall at a position farther from the corona wire electrode than an opening in the lower wall. 2. The corona discharge device according to claim 1, wherein said vibration preventing member is fixed to said lower wall by fusion.