JPS6226756Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a charger used in electrophotographic recording devices and the like.

The purpose of using a charger in an electrophotographic recording device is to (a) uniformly charge or eliminate static electricity on the surface of a chargeable body, and (b) apply corona ions to form an electrostatic latent image on a photoreceptor. (c) It has functions such as forming an electric field to transfer the developed toner image onto paper. In these chargers, dirt, vibration, and the like on the charging wire have a great effect on the output image, so the charging wire requires appropriate tension. Furthermore, since the charged wire is a wire with a diameter of 100 μm or less, it is easily cut or twisted during tensioning, and requires sufficient care when handling.

The structure of a conventional charger will be explained using the front view of FIG. In the figure, 1 is a shield plate serving as the frame of the charger, 2 is a charging wire, 3 is a front block provided with a handle 4 that holds one end 2a of the charging wire 2 and makes it easy to insert and remove the charger, and 5 is a front block. This is a rear block provided with a connector portion 6 for holding the other end 2b of the charging wire 2 and applying high voltage to the charging wire 2. Inside the front block 3, an adjustment piece 8 having a pin on which one end 2a of the charging wire is hooked, and a vibration-proofing pad 9 for suppressing vibration of the charging wire 2 are disposed. The adjustment piece 8 is made vertically movable along a guide surface 10 formed on the front block 3 by means of a screw 11.

In the rear block 5, an adjustment piece 13 having a groove 12 for determining the position near the other end 2b of the charging wire, and an electrode plate 14 for electrically connecting the other end 2b of the charging wire to the connector portion 6 are disposed. It is set up. The adjustment piece 13 is movable up and down along a guide surface 15 formed on the rear block 5 by means of a screw 16. The other end 2b of the charging wire is connected to the electrode plate 14 via a spring 17.

In the above configuration, when changing the distance between the charging wire 2 and the photosensitive drum, it is done by turning the screw 16.
Although the distance between a and the electrode plate 14 changes, the screw 17 absorbs the slack and tensile force of the wire due to this change, and keeps the tension of the charged wire 2 constant at all times.

Next, a method of installing a charging wire in a conventional charger having the above structure will be explained with reference to FIGS. 2a to 2e.

The charging wire 2 is normally wound on a reel 18 and cut as appropriate. First, a ring 2a is formed at one end of the charged wire 2 using a tool 19 such as a hex wrench (FIG. 2a). This ring 2a is hooked onto the pin 7 of the adjustment piece 8 in the front block 3, and the charging wire 2 is fitted into the cutout 9a of the vibration isolating pad 9 (FIG. 2b). Take out a sufficiently long charged wire 2 from the reel 18, hang one end 17a of the spring 17 in the middle, and
7 along the charged wire 2 (FIG. 2c), stop the other end 17b of the spring at a distance of about 3 mm from the hook part 14a of the electrode plate 14, and bend the spring 17. 2c by hand (FIG. 2d), rotate the spring 17 several times to form the ring 2b at the other end, and cut the charged wire. Finally, the other end 17b of the spring is hooked onto the tip of the tool 20, guided to the electrode plate hook portion 14a, and moved to the electrode plate 14 (FIG. 2e).

The above is the conventional method of attaching the charged wire, but this method had the following problems.

(1) When appropriately moving the spring 17 along the charging wire 2, the charger must be firmly fixed. If the charger moves due to the tension acting on the charging wire when the spring 17 is moved, the first ring 2a that is hooked will frequently come off.

(2) Since the position of the spring side end 2b of the charging wire is determined by visual measurement, there is a large variation in the tension of the charging wire when the charging wire is attached. If this tension is too strong, the charged wire tends to break, and if it is too weak, the charged wire tends to vibrate.

An object of the present invention is to provide a corona charger that eliminates the troublesomeness of attaching the charging wire and the variation in the tension of the charging wire, which are the disadvantages of the above-mentioned conventional example.

FIG. 3 shows an embodiment of the present invention. The general structure of the charger is the same as the conventional example described in FIG. 1 above, and the symbols in the figure correspond to those in FIG.
Detailed explanation will be omitted.

21 in the figure is a protrusion on which the charging wire of the present invention is temporarily hooked. This protrusion 21 is formed integrally with a part of the rear block 5, and the position is such that one end 2a of the charged wire is hooked on the pin 7 of the adjustment piece 8, and the ring 2b at the other end is just placed on this protrusion 21. Appropriate tension is generated in the charged wire when it is in a suspended state.

A method for attaching a charging wire to a charger having such a protrusion is as follows. First, the second
After performing the operations shown in Figures a and 2b, the other end of the charging wire 2 is bent around the protrusion 21 on the rear block 5 to form a bent portion 2d, as shown in Figure 4a.
After grasping the bent portion 2c again and removing it from the projection 21, hooking one end 17a of the spring to the formed bent portion 2d (Fig. 4b), and rotating the spring to form the other end ring 2b. Cut the charged wire 2. Finally, as in the case of FIG. 2e, the other end 17b of the spring is hooked onto the electrode plate 14 to complete the tensioning of the wire.

The protrusion 21 is provided on the rear block 5 in which the spring 17 is included, and as an effect of the above structure,
(1) If the projection 21 is provided on the front block 3 without the spring 17, the charging wire will be hung on the support via the spring 17. Therefore, when the charged wire is bent around the protrusion 21, the tension acting on the charged wire may cause the spring to expand, making it impossible to obtain an accurate length of the charged wire.
However, according to the method of the embodiment, it is possible to always set the length of the charging wire to be constant. (2) The second ring of the charged wire is made with the first ring hooked to the pin, so be careful not to remove it. However, by providing the protrusion 21 on the rear block 5 with the spring 17, the spring 17 on which the second ring is to be hung can serve as a tool for making the ring. Therefore, the charging wire does not become loose until the second ring is attached, and the first ring does not easily come off the pin, making the work less cumbersome.

Note that the protrusion 21 is attached to the front block 3 without a spring.
When the charging wire is provided in the spring, a member for fixing the wire may be added so that the charging wire is not affected by the spring when the charging wire is pulled through the spring. Further, the protrusion of the present invention may be provided on only one of the blocks, or may be provided on both blocks at the same time. The member for hooking the charged wire at one point is not necessarily limited to the columnar member described in the embodiment, but may be any structure that allows the charged wire to be caught and bent.

5 to 7 show other protrusion shapes.

Figure 5 shows that the cross-sectional shape of the protrusion has been changed from a circle to a flat shape to reduce the frictional force between the charged wire and the protrusion, making it easier to remove, and Fig. 6 further shows the ridgeline of the protrusion that corresponds to the bent part of the charged wire. The charged wire is slightly tilted toward the other end to make it easier to remove. In Figure 7, a U-shaped or V-shaped groove is created in the part that corresponds to the bent part, and the hook part of the spring is removed before removing the charged wire from the protrusion. is placed in this groove so that a charging wire can be hung on this hook.In this case, the first ring will never come off while the charging wire is removed and the spring is hooked on.

As explained above, in addition to the members that hold both sides of the charged wire, a part of the charger is provided with a protrusion that allows the end of the charged wire to be hooked. This has the effect of suppressing variations in tension and making it easier to attach the charged wire.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional charger, Figures 2a to 2e are explanatory diagrams of the conventional charging wire installation process, and Figure 3
The figure is a front view of the charger of the present invention, Figures 4a and 4b are explanatory diagrams of the method of attaching the charging wire in the charger of the present invention, and Figures 5 to 7 are the protrusions and other parts related to the present invention. It is a perspective view showing a modification of . In the figure, 1 is a shield plate, 2 is a charging wire, 3 is a front block, 17 is a spring, and 21 is a protrusion.

Claims (1)

[Claims for Utility Model Registration] (1) In a corona charger in which the end of a charged wire is fixed to a charged wire holding member via an elastic body, a charged wire is provided in the vicinity of the charged wire holding member in addition to the holding member. A corona charger characterized by having a temporary hooking part. (2) In the corona charger described in claim (1) of the utility model registration, the hooking portion constitutes a protrusion, and the protrusion is set at a position where the charged wire obtains optimum tension after being stretched. A corona charger characterized by: