JPH0792773A - Corona discharger - Google Patents

Abstract

PURPOSE:To simplify the teusively laying work of a discharge wire and prevent breakage and irregular tension of the discharge wire, by mounting an adjusting mechanism at one end of the discharge wire to so as to adjust the tension of the discharge wire following the mounting of a shield case. CONSTITUTION:Insulating blocks 22, 23 are supported on both ends of a shield case 21, and a discharge wire 24 has its one end locked to a recess 26 in the insulating block 22 via a tension adjusting spring 28. A lever 31 is provided in the central position of a recess 30 in the insulating block 23 so as to adjust the tension of the discharge wire 24, and the discharge wire 24 has its one end locked to one end of the lever 31 pivotally supported at its middle and has the other end 34 protruded outward from an opening in the insulating block 23. When the corona discharger is mounted thereon, the other end 34 of the lever 31 is brought into contact with the protrusion 36 of a device frame 35 so that the spring 28 may elongate by a distance as long as one end of the lever 31 is moved to give specified tension to the discharge wire 24. In this way, a specified tension is given to the discharge wire 24 only by setting the corona discharger.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to corona dischargers, and in particular to
The present invention relates to a corona discharger mounted at a predetermined position inside an image forming apparatus.

[0002]

2. Description of the Related Art In a conventional copying machine or the like, an electrostatic latent image is formed on a photoconductor in accordance with image information of an original, and the electrostatic latent image is visualized by a developing device and transferred to a sheet. ing. To form an electrostatic latent image on the photoconductor, a process for charging the surface of the photoconductor to a constant potential is required as a pre-step. As a method of charging the photoconductor,
A method using corona discharge (hereinafter referred to as corona charging) is generally used. The corona discharger used for this corona charging generally has a shield case, a pair of insulating blocks supported at both ends of the shield case, and a discharge wire stretched in the shield case.

In such a corona discharger, a boss portion is provided inside one insulating block, and one end of the discharge wire is attached to this boss portion via a spring. Further, the other insulating block is provided with a fitting recess, and the other end of the discharge wire is clamped and fixed by the engagement of the locking member and the fitting recess. The structure for fixing one end of the discharge wire is, for example, in Japanese Utility Model Laid-Open No. 63-
There is one such as that described in Japanese Patent No. 155146. Here, the body portion of the screw-shaped locking member has a guide portion for guiding the discharge wire and a sandwiching portion having a smaller gap than the guide portion.

Then, the discharge wire is guided by the guide portion and held by the holding portion. Furthermore, if this locking member is press-fitted into the fitting recess provided in the insulating block,
A convex portion provided at a proper position on the body of the locking member is pressed against the fitting concave portion to fix the end portion of the discharge wire.

[0005]

In the conventional corona discharger as described above, while the operator adjusts the tension by visually confirming the length of the spring, the engaging member is engaged with the fitting recess. It is necessary to match the tension, and there is a risk that the tension will vary depending on the operator. Further, it is necessary to engage the engaging member with the fitting recess in a state in which the discharge wire is under tension, and an excessive force is applied to the discharge wire, which may cause disconnection.

The object of the present invention is to provide a corona discharger,
The work to stretch the discharge wire is simplified and the work time is shortened.
The purpose is to prevent disconnection and reduce variations in tension of the stretched discharge wire.

[0007]

A corona discharger according to the present invention is mounted at a predetermined position inside an image forming apparatus, and includes a shield case, a discharge wire stretched in the shield case, and an adjusting mechanism. And have. The adjusting mechanism adjusts the tension of the discharge wire according to the attaching operation when the shield case is attached to one end of the discharge wire and attached to a predetermined position inside the image forming apparatus.

[0008]

In the corona discharger of the present invention, one end of the discharge wire is attached to the adjusting mechanism. The other end of the discharge wire is fixed to the shield case. When the shield case is mounted at a predetermined position inside the image forming apparatus, the adjusting mechanism adjusts the tension of the discharge wire in accordance with the mounting operation.

Here, since the tension of the discharge wire is adjusted by the adjusting mechanism, the work for that purpose is not particularly required, and the variation in the tension can be suppressed.

[0010]

First Embodiment FIG. 1 shows a copying machine having a corona discharger according to a first embodiment of the present invention. In the figure, an original placing table 2 is fixed to the upper surface of a copying machine main body 1. A document holder 3 is mounted on the document table 2 so as to be openable and closable. On the other hand, paper feed cassettes 5 and 6 are detachably mounted on the right side of the copying machine main body 1, and a paper discharge tray 7 for discharging copied paper is mounted on the left side.

Inside the main body 1 of the copying machine, an optical system 8 for reading a document is provided above the main body. A photoconductor drum 9 is arranged substantially in the center of the apparatus main body 1.
Around the photosensitive drum 9, a main charging corona discharger 1 for charging the surface of the photosensitive drum 9 to a predetermined electric charge.
0, a developing device 11, and a corona discharger 1 for transfer for transferring the developed toner image on the photosensitive drum 9 to a sheet.
2. A corona discharger 13 for separating the paper and a cleaning device 14 for cleaning the surface of the photosensitive drum 9 are arranged. Further, between the image forming section formed by the photosensitive drum 9 and the like and the sheet feeding cassettes 5 and 6, a sheet feeding device 15 for conveying the sheet to the image forming section is provided. Further, a sheet conveying device 16 is provided on the downstream side of the image forming unit. A fixing device 18 for fixing the toner image on the conveyed sheet is provided between the sheet conveying device 16 and the discharge roller 17.

As shown in FIG. 2, the main charging corona discharger 10 includes a shield case 21 and a pair of front and rear first and first cases.
It has the second insulating blocks 22 and 23 and the discharge wire 24 stretched in the shield case 21. Note that, in FIG. 2, the vertical direction is reversed. The shield case 21 has a U-shaped cross section and extends along the axial direction of the photosensitive drum 9. A discharge wire 24 is stretched in the space 25 of the shield case 21, and the insulating blocks 22 and 23 are supported at both ends.

Both of the insulating blocks 22 and 23 are formed in a box shape with one side (on the side of the photosensitive drum 9) being open, and the discharge wires 24 are provided on the opposite side walls of the blocks 22 and 23.
Are formed with notches 22a and 23a through which One end of the discharge wire 24 is locked in the recess 26 of the first insulating block 22 via a spring 28 for tension adjustment. An adjustment mechanism is provided in the recess 30 of the second block 23. The adjusting mechanism has a lever 31 rotatably attached by a shaft 32 at a central position of the recess 30 in the width direction (direction perpendicular to the paper surface). The lever 31 is axially supported at its intermediate position, and has a locking hole 33 at one end for locking one end of the discharge wire 24. Also, the other end 34
Protrude outward from the opening of the second insulating block 23.

This corona discharger 10 comprises a photosensitive drum 9
Is mounted above and is positioned and fixed by the convex portion 36 of the device frame 35. When the corona discharger 10 is mounted, the other end 34 of the lever 31 comes into contact with the protrusion 36 of the device frame 35. Next, the operation of attaching the discharge wire and adjusting the tension will be described.

One end of the discharge wire 24 is fixed to the first insulating block 22 via a spring 28, and the cutouts 22a and 2a are formed.
It passes through 3a and is attached to the locking hole 33 of the lever 31. At this time, the discharge wire 24 is stretched loosely so that the spring 28 does not stretch, and one end of the lever 31 is pulled toward the first insulating block 22 side. Therefore, the other end portion 34 of the lever 31 is inclined to the outside of the shield case 21 as shown in FIG.

The corona discharger 10 is attached to the device frame 35.
When it is installed in the predetermined position of the lever 3, as shown in FIG.
The other end 34 of 1 hits the projection 36, and the lever 31 rotates against the biasing force of the spring 28. The spring 28 extends by the distance moved by the one end of the lever 31 and can apply a predetermined tension to the discharge wire 24. According to this embodiment, the tension is not excessively applied when the discharge wire 24 is stretched, so that disconnection can be prevented. Also,
A predetermined tension can be applied to the discharge wire 24 simply by setting the corona discharger 10 inside the device.

Second Embodiment FIGS. 4 and 5 show a corona discharger 37 according to a second embodiment. In this embodiment, the device frame 40 to which the corona discharger 37 is positioned and fixed has a box-shaped mounting portion 38 that opens downward (on the side of the photosensitive drum), and is inclined downward on its inner side. It has a slope 39.

The second insulating block 41 on the inner side of the device of the corona discharger 37 has a slope 39 of the chassis 40 at the lower end.
It has a convex portion 42 having the same inclination as. A through hole 43 is formed in the lid portion of the second insulating block 41, and a pin 44 is inserted into the through hole 43. A spring 45 is mounted between the head of the pin 44 and the lid of the insulating block 41.
Is biased downwards. One end of the pin 44 is the rotating member 4
It is connected to the support member 47 via 6. Rotating member 4
Both ends of 6 are rotatably connected to a pin 44 and a support member 47, respectively. Then, an engaging hole 48 to which an end of the discharge wire 24 is attached is provided in an intermediate portion of the rotating member 46.
Is provided. Further, the support member 47 is fixed inside the second insulating block 41.

The lower surface of the first insulating block 22 is provided with a convex portion 49 which serves as a support portion when the corona discharger 37 is prevented from coming off and is positioned and fixed. Also,
A leaf spring 50 is provided on the upper wall 38 of the mounting portion 38 and urges the corona discharger 37 downward. Next, the operation of attaching the discharge wire 24 and adjusting the tension will be described.

One end of the discharge wire 24 is fixed in the first insulating block 22 via the spring 28, and the other end is attached to the locking hole 48 of the rotating member 46 in the second insulating block 23. In this state, the discharge wire 24 has the spring 28
The tension is set so that it does not stretch. In this state, the corona discharger 37 is mounted on the mounting portion 38 of the device frame 40. In this case, the protrusion 42 of the corona discharger 37 is in contact with a part of the mounting portion 38, and is inserted while pressing the leaf spring 50. The pin 44 projects downward due to the urging force of the spring 45, and the locking hole 48 of the rotating member 46 is located below the tip of the support member 47, as shown in FIG.

When the convex portion 42 reaches the position of the slope 39 of the mounting portion 38, the shield case 21 is biased downward by the leaf spring 50, so that the convex portion 42 slides down on the slope 39. Then, the head of the pin 44 is pushed upward. As a result, the rotating member 46 rotates about the tip of the support member 47, and the locking hole 48 moves upward from the tip position of the support member 47, as shown in FIG.

Therefore, the discharge wire 24 is brought into contact with the lower end edge of the support member 47 and tension is applied. With such an embodiment, the same effect as the above embodiment can be obtained.

[0023]

According to the present invention, when the discharge wire is stretched, the tension is not excessively applied, and the breakage of the wire can be prevented. Further, a constant tension can be applied only by fixing the present corona discharger at a predetermined position, and it is possible to eliminate variations in tension depending on the operator. Further, the work at the time of refilling is simplified and the work time can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional configuration diagram of a copying machine to which an embodiment of the present invention is applied.

FIG. 2 is a side sectional view of the corona discharger according to the first embodiment of the present invention.

FIG. 3 is a side sectional view showing a state where the corona discharge part is attached.

FIG. 4 is a side sectional view of a corona discharger according to a second embodiment of the present invention.

FIG. 5 is a side sectional view showing a state where the corona discharger is attached.

[Explanation of symbols]

 24 Discharge Wire 31 Lever 44 Pin 46 Rotating Member 47 Supporting Member

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Haruichi Shirasaki 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Kenichi Tanabe 1-228 Tamatsukuri, Chuo-ku, Osaka No. Mita Kogyo Co., Ltd. (72) Inventor Hiroshi Ito 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (72) Yasunori Ueno 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Within Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A corona discharger mounted at a predetermined position inside an image forming apparatus, wherein a shield case, a discharge wire stretched in the shield case, and one end of the discharge wire are attached. A corona discharger comprising: an adjusting mechanism that adjusts the tension of the discharge wire in accordance with the mounting operation when the shield case is mounted at a predetermined position inside the image forming apparatus.