JPH02267571A - Corona electrifier - Google Patents

Abstract

PURPOSE:To simplify constitution and to prevent the decrease of tension of a grid plate with age by equaling the distance between the detaining edges of detaining holes at both ends of the grid plate to the distance along a folding edge passing the positioning edge between the detaining faces of bodies of detaining parts. CONSTITUTION:The bodies of the grid plate detaining parts 11 provided on end blocks 6, 8 have the sufficient rigidity to prohibit the deformation by the tension of the grid plate 1. The distance along the folding line passing the positioning edges 13 between the detaining faces of the respective detaining parts 11 is nearly equal to the distance between the detaining edges of the detaining holes of the plate 1. Such ribs 12 into which the detaining edges of the plate 1 are bitten in the case of detaining the plate 1 by applying tension thereto and with which the plate 1 maintains the prescribed tension in the stopped state of the biting are provided on the detaining faces of the bodies of the detaining parts 11. After the plate 1 is held by the prescribed tension, the plate is flattened between the positioning edges 13, by which the prescribed positional relation is maintained between a corona discharge wire 2 and a shielding case 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a corona charging device in which a corona wire is stretched inside a shield case and a grid is provided at the opening of the shield case.

Joki Dan 1 Supervision Removal and removal of photoreceptors in image forming devices using electrostatic photographic processes such as electrophotographic copiers, laser printers, and facsimiles.
As a charger, a transfer charger, and a separate charger, a so-called thin wire type corona discharger, in which a thin wire of tungsten or the like is stretched inside a gutter-shaped shield case, is often used. Furthermore, a so-called scorotron type corona charging device is also widely used, which is capable of controlling the amount of charge removed by providing a grid plate covering the opening surface of the shield case and applying a voltage to the grid plate.

In a scorotron type corona charging device, the mutual positional relationship between the corona discharge wire, the grid plate, and the shield case is important, and in order to maintain this at a predetermined value, the corona discharge wire is installed at both ends of the shield case. The grid plate is stretched between the dielectric end blocks, and the grid plate is also stretched between the positioning edges provided on the end blocks on both sides.

As a method of applying tension to the grid plate, for example, Japanese Utility Model Application Publication No. 58-159545 and Japanese Utility Model Application No. 62-3026 are used.
As seen in Publication No. 8, etc., the common method is to lock the end block through a spring such as a coil spring or a plate spring, but this method increases the number of parts and the number of assembly steps. In addition, in order to stretch a grid made of metal plates in a flat shape, a relatively large tension spring is required, and the grid plate may become sagging or curved due to deterioration of the spring over time. , the distance to the photoreceptor or corona discharge wire may be incorrect.

The locking hole at the end of the grid plate is manufactured by molding the locking part at the end of the grid plate integrally with the end block as a columnar part that bends elastically when tension is applied, without using a spring. For example, there is a method of applying tension to the grid plate by bending the columnar part and hooking it to lock it.
2-143961, etc., and it is useful for reducing the number of parts and facilitating assembly, but if creep occurs over time in the columnar locking part, the grid plate can be Corona discharge wire becomes sagging,
The disadvantage is that the distance to the photoreceptor is incorrect.

In addition, a configuration in which the grid plate was made of sheet metal integrally with the shield case to give it rigidity and maintain a predetermined shape and positional relationship with the corona discharge wire was developed in 1983.
-89862 and Japanese Utility Model Application Publication No. 62-140544, it is possible to reduce the number of parts and make assembly easier, but the line width is thicker than the mesh part of the etched grid plate. The disadvantage is that the pitch becomes rough, making it difficult to maintain charging stability.

In view of the above-mentioned drawbacks of the conventional grid plate tensioning means for a corona charging device with a grid plate, the present invention provides a corona discharge method that is simple in structure and has little risk of reducing the tension of the grid plate over time. The task is to provide equipment.

In the corona charging device of the present invention, in order to solve the above-mentioned problems, the main bodies of the grid plate locking parts provided on the above-mentioned both side end blocks have sufficient rigidity not to be deformed by the tension of the grid plates, The distance between the locking surfaces of the locking parts on both sides along the fold line passing through the positioning edge is approximately equal to the distance between the locking edges of the locking hole of the grid plate, and the distance between the locking surfaces of the locking parts on both sides is approximately equal to the distance between the locking edges of the locking hole of the grid plate, When the grid plate is locked under tension on the locking surface of the main body of the grid plate locking part, the locking edge of the grid plate easily bites, and the grid plate maintains the specified tension when the biting stops. The invention is characterized by having at least one rib that makes it look like this.

Shoji 1 With the above configuration, if the locking holes provided at both ends of the grid plate are locked to the locking portions provided on both end blocks, and the end blocks are attached to the predetermined position of the shield case, , since the distance between the locking edges of the locking holes at both ends of the grid plate is equal to the distance along the fold line passing through the positioning edge between the locking surfaces of the locking part main body, The locking edges of the grid plate bite into the ribs, and when the biting stops, the grid plate is stretched with a predetermined tension, becomes flat between the positioning edges, and the corona discharge wire.

A predetermined positional relationship with the shield case can be maintained. The locking part has sufficient rigidity to not be deformed by the tension of the grid plate, so it does not deform over time and maintains a predetermined tension over a long period of time, and the grid plate is kept flat between the positioning edges, preventing corona discharge. Maintain a predetermined positional relationship with the wire and shield case.

1-5 Below, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof.

The corona charging device of this embodiment includes a gutter-shaped shield case 3 and dielectric end blocks 6 provided at both ends of the shield case 3.
．． 8, and a corona discharge wire 2 whose both ends are locked to these end blocks 6.8 and stretched inside the shield case 3.
and a grid plate 1 that covers the opening of the shield case 3 and is stretched between both end blocks 6 and 8.

Bosses 101 and 102 are drilled on the side surface of the end block 6, and correspondingly, a slit 18 is provided on the side surface of the shield case and the left end in the figure is open. 18 , and the boss 102 is positioned in a state where it is in contact with the inner part of the slit 18 . On the other hand, the end block 8 is provided with bosses 103 and 104, and correspondingly, the shield case is provided with a hook-shaped slit 19 with an open upper end and a long hole 20.
．． 104 is fitted into this, and the boss 103 is brought into contact with the left end of the hook-shaped portion of the slit 19 to be positioned at a predetermined position. It can be moved between a non-protruding position and a non-protruding position.

A ball 17 is provided on the end block 6 in a direction perpendicular to the longitudinal direction of the corona discharger.
is a metal power supply bracket 5 with a hook portion at the tip.
is attached from the outer end side through the fitting hole, and the annular terminals 2a and 2b fixed to both ends of the corona discharge wire 2 are locked to the ball 17 and the hook portion of the power supply bracket 5 via the spring 4, The wire is stretched with a predetermined tension by supporting the vicinity of both ends in the V-shaped groove 14 provided in the rising part of the inner end of the end block 6.8.

In addition, each end block 6.8 has a grid plate locking portion 1.
1 is provided protruding from the top. The locking part 11 is shown in FIG. 3(a).
, (b), (c), and (d), it has a hook-shaped portion protruding from both ends of the grid plate 1, and locks the locking holes 15a and 15b drilled at both ends of the grid plate 1. It has enough rigidity that it hardly bends even when tension is applied, and when tension is applied by locking the locking holes 15a and 15b of the grid plate on the locking surface, the grid will be fixed as shown in Fig. 4. Ribs 12 are provided so that the edge of the locking hole of the plate can easily bite into the grid plate and maintain a predetermined tension in a state where biting has stopped. A locking part 11 is provided at the upper end of the rising part of the inner end of each end block.
A positioning edge 13 is provided to support and position the grid plate that is engaged with the grid plate. In addition, end block 6.
8 is fitted with a cover 7.9 which covers the above-mentioned opening of the cavity in which the corona discharge wire 2 is provided.

A procedure for attaching a corona discharge wire and a grid plate to the corona charging device having the above configuration will be explained.

Terminals 2a and 2b are fixed to both ends of the wire 2, and the wire 2 is passed through the V-shaped groove 14 provided in the rising part inside the end block 6.8. Power is supplied to the terminal 2a to the ball 17 and to the terminal 2b via the spring 4. It is locked to the hook of bracket 5. Thereafter, a cover 7.9 is attached to the opening of the empty space of the end block 6.8 to cover it.

Next, on the grid plate locking part 11 of the end block 6.8,
Two locking holes 15 are provided at each end of the grid plate 1.
a and 15b are locked.

The end block 6 in the above condition is its boss 101.10
2 is fitted into the guide groove 18 of the shield case 3, and then the boss 103 of the end block 8 is fitted into the guide groove 19 of the shield case 3.

The distance X between the inner sides of the locking holes of the grid plate (see Figure 2) is the distance between the ribs 1 of the locking part 11 of the end block 6.8 attached to a predetermined position of the shield case, as shown in Figure 5.
A broken line p, p, p, p passing through the positioning edges p, p, p4 at the upper end of the rising part of the end block with the anchoring points p,, p, of the rib 12 in the state where the grid plate bites into the grid plate 2 as both ends, p, p, p, ,
It is set approximately equal to the length of .

Therefore, with no tension applied to the grid plate and the edges of the locking holes of the grid plate 2 not biting into the ribs, the rib locking points Pyu, P are both ends, and the rising portions of the end blocks 6 and 8 are The length of the broken line P□P3P, P passing through the upper edges p, , p is greater than X, and the guide groove 19 is hook-shaped, so the end block 8 will not touch the bottom when assembled. It is not possible to insert the boss 103 into the guide groove 19 with it facing down.
Therefore, the end block 8 is set to p4 shown in FIG. p, when the boss 103 is tilted so that the point approaches the end block 6 on the opposite side, the boss 103 is passed through the guide groove 19, and when it reaches its lower end, it is gradually raised to the correct position, tension is applied to the grid plate 2, and the rib 12 The tension of the grid plate 2 reaches a predetermined value at the position where the grid plate 2 bites into the locking portion and the boss 103 abuts the end of the hook-shaped portion of the guide groove. At this time, the boss 104 is projected by the spring force and fitted into the elongated hole 20, and the end block 8 is fixed in the correct posture and position relative to the rigid shield case 3. Note that the boss 104 may be inserted from the outside and attached to the end block, and in this state, a predetermined tension is applied to the grid plate 1. Since the grid plate locking portion 11 of the end block 6.8 has sufficient rigidity, even if tension is applied to the grid plate 1, it will not deform over time, and the grid plate will maintain a predetermined tension over a long period of time. The surface is kept flat.

ABS resin or the like is suitable as the material for the end block, and the new surface shape of the rib may be an isosceles triangle with a width and height of about 0°31.

Also, the material of the grid plate is SUS 304-CS.
P-H thickness O, about 1 m is suitable P□P3
P, P, = 260.3 ± 0.4 (after tolerance accumulation) P, P
, P, P, = 260.9 ± 0.4 (>, good results were obtained.

As described above, according to one aspect of the present invention, a grid of a corona charging device equipped with a grid is held in a flat state under tension, and a grid plate and a corona discharge wire are connected to each other.

The distance between the shield cases can be maintained constant over a long period of time, and the required charge removal and charging performance can be maintained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the corona charging device of the present invention, FIG. 2 is an exploded perspective view thereof, and FIG. 3 is (a), (
b), (c), and (d) are respectively a perspective view, a front view, a side view, and a top view of the grid plate locking portion, and FIG. 4 is a side view showing a state in which the grid plate is locked to this locking portion. FIG. 5 is an explanatory view for explaining the effect. 1...Grid plate 2...Corona discharge wire 3...Shield case 6.8...End block 11...Grid plate locking part 12...Rib 13...Grillard plate positioning edge 14 ...7-shaped grooves 101 to 404...Boss Fig. Fig. 1 Fig.

Claims (1)

[Claims] (1) A gutter-shaped shield case, a corona discharge wire stretched between dielectric end blocks fixed to both ends of the shield case, and a corona discharge wire stretched between the end blocks made of a dielectric material fixed to both ends of the shield case, and locking parts provided at both ends of the shield case. The stop holes are locked and supported by positioning edges provided at the inner ends of both end blocks, and a grid plate is stretched between the corona discharge wires and the corona discharge wire, covering the opening surface of the shield case and maintaining a predetermined interval. In the corona charging device, the main bodies of the grid plate locking parts provided on both end blocks have sufficient rigidity not to be deformed by the tension of the grid plate, and the positioning edges between the locking surfaces of the locking parts on both sides are The distance along the fold line passing through is approximately equal to the distance between the locking edges of the locking hole of the grid plate, and the grid plate is placed under tension on the locking surface of the grid plate locking part body provided in the end block. The invention is characterized by the provision of at least one rib that allows the locking edge of the grid plate to easily bite into the grid plate when it is hooked and locked, and that the grid plate maintains a predetermined tension when the biting stops. Corona discharge device.