JPH0667515A - Electrifying device for image forming device - Google Patents

Abstract

PURPOSE:To provide the electrifying device for the image forming device where a charge wire is in parallel to a photosensitive drum only by setting a charge case with a charge wire expanded on it to a specified position and its surface potential can be made uniform. CONSTITUTION:Wire supporting members 22a and 22b are attached to fixing members 16a and 16b provided on both side of the photosensitive drum 1 in the axial direction able to be swung around in the axial direction of the photosensitive drum 1 through bearing members 17a and 17b. When the charge case 4 where the charge wire 10 is expanded is moved along a guide rail 3 disposed in the axial direction of the photosensitive drum 1, the wire supporting members 22a and 22b are swung and inserted to the charge case 4 along with that movement, the charge wire 10 is put into a state of tension by being supported while being pressurized and the charge wire is set to be in parallel to the surface of the photosensitive drum while maintaining that state. When the charge case 4 is separated from the guide rail 3, the charge wire 10 is released by the swing of the wire supporting members 22a and 22b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device in an image forming apparatus such as an electrostatic photocopier and a printer.

[0002]

2. Description of the Related Art A charging device in which a charge wire is stretched in a charge case is used for a main charging device, a transfer device, a separating device, etc. in an image forming apparatus such as an electrostatic photocopier. There is. The charging device is arranged in parallel to the axis of the photosensitive drum, facing the peripheral surface of the photosensitive drum. The charge wire is parallel to the photosensitive drum so that the surface potential in the axial direction of the photosensitive drum is uniform. It is necessary to

As the charging device, for example, a coil-shaped spring attached to one end of a charge wire is attached to one inner end of a charge case having a concave cross section, and the other end of the charge wire is attached to the charge case.
In this manner, both ends of the charge wire installed in the charge case in a erected manner are supported by being pushed by the pair of wire support members provided inside the charge case, so that the spring is slightly extended. , Apply tension to the charge wire to maintain the linear state. And
One of the pair of wire supporting members is configured to be movable in the depth direction of the charge case, and the wire supporting member is supported by the adjusting screw. Therefore, it is known that the charge wire is moved by advancing and retracting the wire support member by the rotation of the adjusting screw to adjust the parallelism of the charge wire with respect to the photosensitive drum to make the surface potential uniform.

[0004]

The above-mentioned conventional charging device adjusts the surface potential by moving one end side of the charge wire as the wire supporting member advances and retracts due to the rotation of the adjusting screw. The amount of advance / retreat of the adjusting screw varies depending on the amount of rotation thereof and is not constant. Therefore, if the charge wire whose surface potential has been adjusted as described above is cut, it is necessary to replace the charge wire with a new one. At that time, since the adjusting screw can freely rotate, the exchanged charge wire and photosensitive The parallelism with the drum changes, causing a difference in surface potential. For this reason,
It is necessary to adjust the position of the charge wire by rotating the adjustment screw every time the charge wire is replaced, etc., which increases the time required for maintenance and other tasks.
In addition, there is a problem that the charge wire is unevenly adjusted.

The present invention is intended to solve the above-mentioned problems, and it is not necessary to adjust the position of the charge wire with respect to the charge case, and only by setting the charge case in which the charge wire is stretched at a predetermined position, An object of the present invention is to provide a charging device of an image forming apparatus in which a charge wire is parallel to a photosensitive drum and the surface potential of the charging wire can be set uniformly.

[0006]

In a charging device for an image forming apparatus of the present invention, a charge case in which a charge wire is stretched is constructed so that it can be mounted on a guide rail provided in the axial direction of the photosensitive drum. The supporting member is swingably attached to a fixing member provided on both sides in the axial direction of the photosensitive drum, and the wire supporting members are swung in the same direction as the charge case is moved. The wire support member is projected from the peripheral surface of the photosensitive drum, and while maintaining that state, the charge wire is pressed to support and tension the wire, and the charge case is moved in the same direction by separating it from the guide rail. It is characterized in that the wire supporting member is swung to release the charge wire.

The swing of the wire support member accompanying the movement of the charge case may be performed by, for example, projecting a locking piece on the wire support member and locking a part of the charge case on the locking piece, or by charging the charge case and the wire. It can be performed by any means such as frictional force with the bearing member.

[0008]

In the charging device for the image forming apparatus of the present invention, when the charge case is separated from the guide rail, each wire support member also swings in the same direction as the charge case moves, for example, each wire support member. The member is in the same direction as the axis of the photosensitive drum. In this state, when the charge case in which the charge wire is stretched is attached to the guide rail and moved, the wire support member swings in the same direction as the charge case moves to the upright state. Each wire support member supports the charge wire while pushing the charge wire away from the photosensitive drum, thereby tensioning and maintaining the charge wire. As described above, since the charge wire is supported by the pair of wire support members axially attached to the fixing member and the tension state is set, and the distance between the surface of the photosensitive drum and the charge wire is set, the position of the charge wire with respect to the charge case is adjusted. Is unnecessary.

Therefore, if the distances between the respective wire bearing portions of the pair of wire bearing members and the surface of the photosensitive drum are made to coincide with each other, the surface of the photosensitive drum and the charge wire are irrespective of the position of the charge wire in the charge case. Can always be set to be constant over its entire length, and it is not necessary to adjust the position of the charge wire in the conventional example when the charge wire is exchanged.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a charging device of an image forming apparatus of the present invention will be described with reference to FIGS. In the figure, 1 is a photosensitive drum, 2 is a shaft support of the photosensitive drum 1, and 3 is a guide rail provided at a distance from the surface of the photosensitive drum 1 and extending in the axial direction thereof. (Not shown)
It is stuck to. As shown in FIG. 5, the guide rail 3 is formed by bending the front end portions of the opposing walls of the rail main body 3a having a concave cross section inwardly of the rail main body 3a and engaging walls 3b, 3b.
Is provided.

Reference numeral 4 denotes a charge case having a concave cross section, in which a handle 5 is provided on the outer surface of one end in the longitudinal direction and a connecting plate 6 is provided on the outer surface of the other end. 7a is a connecting plate 6 at the end faces of the opposing walls 4a, 4a in the charge case 4.
Is a locking step provided on the side end, 7b is a locking step provided on the end of the opposing walls 4a, 4a on the handle 5 side,
8a and 8b are wire support plates provided at both ends of the charge case 4, 9 is a lead plate made of a conductive material provided from the connection plate 6 to the inside of the charge case 4, and 10 is the wire support plate 8a, With the charge wire supported by 8b, one end of a coil-shaped spring 11 connected to one end of the charge wire is attached to the lead plate 9, and the other end of the charge wire 10 is fixed to the charge case 4 with a mounting screw 12. There is.

Reference numerals 13 and 13 denote locking members provided at both ends in the longitudinal direction of the outer surface of the bottom wall 4b of the charge case 4, and these are supporting portions 14 fixed to the bottom wall 4b as shown in FIG. At the tip end of the bottom wall 4b, which is projected on both sides in the width direction of the bottom wall 4b, and is inserted into the guide rail 3 and the locking wall 3
It is formed so that it can be locked to b and 3b. Reference numeral 15 is a leaf spring attached to the outer surface of the intermediate portion in the longitudinal direction of the bottom wall 4b, the end portion of which is fixed to the bottom wall 4b, and the other end side is inclined and separated from the bottom wall 4b. As described above, when the locking member 13 is inserted and locked in the guide rail 3, the leaf spring 15 is brought into pressure contact with the inner surface of the guide rail 3 to stabilize the charge case 4.

Fixing members 16a and 16b are provided on the sides of the shaft supports 2 and 2 and are fixed to the frame of the image forming apparatus. Reference numerals 17a and 17b denote bearing members, and as shown in FIG. 6, a receiving plate 19 bent substantially at a right angle is projected from the end of the mounting portion 18, and the opposite side of the receiving plate 19 is provided. The bearing parts 20, 20 facing each other at both ends of the mounting part 18.
The mounting portion 18 is provided with a mounting screw hole 21. Reference numerals 22a and 22b denote wire supporting members, which are, as shown in FIG. , Support plates 24, 24 having the support plate 23 side as a flat surface are projected,
A locking projection (25) is projected on one side in the thickness direction, and a wire support recess (26) is provided at the tip of the support plate (23). The wire support members 22a, 22b configured as described above are pivotally mounted on the support plates 24, 24 so as to be swingable between the bearing portions 20, 20 (see FIG. 4). Then, when the mounting portions 18 of the bearing members 17a and 17b and the support plate 23 are in a parallel state, the locking projection 25 projects in the opposite direction to the support plate 19, and the support plate 23 is placed on the support plate 19 side. When it is swung, the support plate 23 overlaps the support plate 19 (see the chain line in FIG. 4) and stops.

Then, the fixing screws 27 penetrating the fixing members 16a and 16b are screwed into the respective mounting screw holes 21 of the bearing members 17a and 17b so that the wire supporting members 22a and 22b are axially aligned with the photosensitive drum 1. Fixed member so that it swings on
Bearing members 17a and 17b are attached to 16a and 16b. Here, as shown in FIG. 4, the mounting hole 28 provided in the fixing member 16b for penetrating the fixing screw 27 is a long hole extending in the same direction as the depth direction of the charge case 4 to form a bearing. Member 17
It enables adjustment of the mounting position of b. Further, when the charge case 4 is mounted on the guide rail 3, the locking step 7a of the charge case 4 is locked to the locking projection 25 of the wire support member 22a, and the locking step 7b is locked to the wire support member 22b.
Wire bearing members 22 to enable locking to 25 respectively.
The support plate of the wire support member 22b is longer than the support plate 23 of a.
The length of 23 is formed to be as long as the height of the locking step portion 7a. 29
Is a stopper that stops the charge case 4 by contacting the connection plate 6 when the charge case 4 is mounted on the guide rail 3. The lead plate 9 comes into contact with the stopper 29 to apply a voltage to the charge wire 10. The applying electrode 30 is attached.

To set the charging device of the image forming apparatus, as shown in FIG. 3A, the locking members 13, 13 are sequentially inserted into the guide rail 3 from the side of the connecting plate 6 of the charge case 4. Then, the charge case 4 is slid along the guide rail 3. At this time, the wire support member 22a,
Since 22b is in the same direction as the axis of the photosensitive drum 1 and each locking projection 25 projects to the charge case 4 side, the locking projection 25 and the charge case 4 are locked. The steps 7a and 7b are opposed to each other in the sliding direction of the charge case 4. Therefore, when the charge case 4 slides, the locking step portions 7a, 7b are pushed into the locking projections 25 so as to push the wire supporting members 22a, 22b in the same direction as the charge case 4 slides. Each support plate 23 is inserted into the charge case 4 by swinging in the direction.

As the wire support members 22a and 22b swing, the support recesses 26 of the respective support plates 23 become
Since 10 contacts and pushes the charge wire 10 in the direction away from the photosensitive drum 1, the charge wire 10 extends the spring 11 and becomes a tension state. In this manner, when the wire support members 22a and 22b swing as shown in FIG. 3B until they are substantially in the same radial direction as the photosensitive drum 1,
After that, as shown in FIG. 5, the end faces of the opposing walls 4a, 4a of the charge case 4 overlap with the planes of the support plates 24, 24, so that the support plates 24, 24 cannot rotate. Because
The wire support members 22a and 22b support the charge wire 10 while maintaining the state.

On the other hand, the charge case 4 has its connecting plate 6
Comes into contact with the stopper 28 and stops, and the lead plate 9 becomes an electrode.
Connected to 29. In this state, when the balance of the surface potential in the length direction of the charge wire 10 is poor, the bearing member
Loosen the fixing screw 27 of 17b, move the bearing member 17b within the length of the mounting hole 28 of the fixing member 16b, adjust the position of the charge wire 10 via the wire supporting member 22b, Balance the potential. If you slide the charge case 4 away from the guide rail 3,
The movement of the charge wire 10 causes the wire support members 22a and 22a to move.
Swing b in the same direction. Wire support members 22a, 22b
Is stopped by being supported by the receiving plate 19 as shown in FIG.

As described above, in this charging device, the bearing member 16 is attached to the fixing members 16a and 16b on both sides of the photosensitive drum 1 in the axial direction.
With the wire support members 22a and 22b attached via a and 16b, the charge wire 10 of the charge case 4 mounted on the guide rail 3 is supported to bring the charge wire 10 into a tensioned state and to the surface of the photosensitive drum 1. Charge wire 10
The position of is set. Therefore, it is not necessary to adjust the position of the charge wire 10 with respect to the charge case 4. When the charge wire 10 is supported by the wire supporting recesses 26 of the wire supporting members 22a and 22b, the distance between the wire supporting recesses 26 and the surface of the photosensitive drum 1 changes the positions of the bearing members 16a and 16b. It is immutable unless you do.

Therefore, when the charge wire 10 is supported, the distance between the wire supporting recesses 26 of the wire supporting members 22a and 22b and the surface of the photosensitive drum 1 can be determined by, for example,
Adjust when setting up the image forming apparatus. Then, after that, even if the position of the charge wire 10 in the charge case 4 is changed by exchanging the charge wire 10 or the like, if the charge case 4 is mounted on the guide rail 3, the charge wire 10 and the photosensitive wire are exposed. The distance from the surface of the drum 1 becomes equal over its entire length, and the surface potential becomes uniform,
No adjustment is required to make the surface potential uniform. Therefore, the maintainability is improved, the time required for it can be shortened, and the unevenness of the adjustment of the surface potential can be eliminated.

[0020]

As described above, in the charging device of the image forming apparatus of the present invention, the pair of wires swingably attached in the axial direction of the photosensitive drum to the fixing members provided on both sides of the photosensitive drum in the axial direction. The support member supports the charge wire of the charge case mounted on the guide rail while pushing the charge wire to bring the charge wire into a tension state and set the position of the charge wire with respect to the surface of the photosensitive drum. Therefore, it is not necessary to adjust the position of the charge wire with respect to the charge case. Moreover, if the distance between the wire bearing portion of the pair of wire bearing members and the surface of the photosensitive drum is properly adjusted, for example, when the image forming apparatus is set up, it is necessary to move the position of the wire bearing member thereafter. It does not happen.

Therefore, even when the charge wire of the charge case is replaced, the charge wire is supported by the pair of wire support members only by mounting the charge case on the guide race. Since the surface potential of the drum is made uniform by making the distance to the surface of the drum equal over its entire length, no adjustment is required to make the surface potential uniform. Therefore, the maintainability can be improved and the time required for it can be shortened.
In addition, it is possible to eliminate uneven adjustment of the surface potential.
The support of the charge wire by the wire support member and its release are performed by the swing of each wire support member, and the swing operation of the wire support member is performed along with the mounting of the charge case on the guide rail and the movement at the time of separation. Therefore, the swing operation of the wire support member can be performed easily and appropriately.

[Brief description of drawings]

FIG. 1 is an overall perspective view of an embodiment of the present invention.

FIG. 2 is an exploded bottom perspective view of the charge case according to the embodiment.

FIG. 3 is a cross-sectional explanatory view of mounting the charge case of the embodiment.

FIG. 4 is an enlarged cross-sectional view of the mounting portion of the adjustable bearing member of the embodiment.

FIG. 5 is an enlarged cross-sectional side view when the charge case of the embodiment is attached.

FIG. 6 is an enlarged perspective view of a bearing member and a wire support member of the embodiment.

[Explanation of symbols]

1: photosensitive drum, 3: guide rail, 4: charge case, 7a, 7b: locking step, 10: charge wire, 16a, 16b:
Fixed member, 17a, 17b: Bearing member, 22a, 22b: Wire support member.

Claims (1)

[Claims] 1. A charge case in which a charge wire is stretched is configured to be attachable to a guide rail provided in the axial direction of the photosensitive drum, and a pair of wire bearing members is fixed to both sides in the axial direction of the photosensitive drum. The members are swingably attached to the members, and as the charge case is moved, the wire supporting members are swung in the same direction so that the wire supporting members project from the peripheral surface of the photosensitive drum and It is characterized by releasing the charge wire by supporting each of the wire support members in the same direction with the movement of separating the charge case from the guide rail by supporting the charge wire while pushing the charge wire. A charging device for an image forming apparatus.