JPH055564Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a charger used in electrophotographic devices and the like.

"Prior Art" In an electrophotographic apparatus, after the surface of a photoreceptor is uniformly charged with a charger that performs corona discharge,
A toner image is formed by attaching toner to the electrostatic latent image formed by exposing the original image to this photoreceptor, and this toner image is transferred to a suitable paper and then fixed, thereby obtaining a copy. ing.

In the conventional general charger 1 shown in FIGS. 6 to 8, the shield case 2 is formed into a channel-like structure that is open upward. An intake plate 4 having a plurality of intake ports 3 is fixed inside the shield case 2, and insulation blocks 5 and 6 having support plates 5a and 6a at their inner ends are respectively fixed to both ends of the intake plate 4. The discharge wire 7 made of a thin metal wire is positioned by notches 8 and 9 formed in each support plate 5a and 6a, respectively.
They are locked to the insulating blocks 5 and 6, respectively.

A power supply terminal 11 connected to a high voltage power source is connected to the outer end of the insulating block 5. Further, the suction chamber 13 formed by the bottom plate of the shield case 2 and the suction plate 4 is sucked by a suction pipe 12 connected to a suction blower (not shown), and is passed through a filter (not shown) to the outside of the copying machine. is discharged.
The intake port 3 is arranged at a position away from directly under the discharge wire 7 to reduce adhesion of foreign matter to the discharge wire 7.

The charger 1 that performs corona discharge has a high voltage (5~
10KV) is applied to the discharge wire 7, both insulating blocks 5 and 6, which are the supporting parts of the discharge wire 7,
is made of high insulating material. For example, as highly insulating materials, Noryl (PPE), unsaturated polyester (BMC), flame-retardant polypropylene, etc. are used.

"Problems to be solved by the invention" The insulating blocks 5 and 6 in the charger described above are
Even if the insulation is good, deterioration over time and adhesion of foreign matter to the surface will cause a phenomenon in which current flows along the surface, so-called creeping leakage. When this creepage leak occurs,
There are problems such as copy omissions, machine malfunctions due to discharge noise, and problems such as smoke and fire.

As a countermeasure to the above problem, discharge wire 7
Increase the insulation distance between and shield case 2,
Means such as cutting off high voltage are known.
The method described above goes against the goal of downsizing and energy saving of the charger, while method 2 has the disadvantage that the machine frequently stops, causing inconvenience to the user.

The object of the present invention is to provide a charger that eliminates the above-mentioned drawbacks.

"Means for Solving the Problem" The charger of the present invention has an insulating block installed in an insulating auxiliary case so as to be separated from the surrounding surface thereof, and a position corresponding to the auxiliary case. By forming a notch at the end of the shield case 2 and detachably providing an insulating cover on the auxiliary case, creepage leakage of the insulating block toward the shield case is prevented.

"Embodiment" An embodiment of the present invention will be described below based on the drawings.

Components having the same functions as those in FIGS. 6 and 7 are designated by the same reference numerals, and their explanations will be omitted.

In FIGS. 1 to 3, an insulating block 2 is provided with positioning protrusions 21a and 22a on the upper part of the inner end on the discharge side.
Each end of the discharge wire 7 is secured to the upper portions of the discharge wires 1 and 22 by screws 23 and 24, respectively. The insulating blocks 21 and 22 have inner surfaces separated from their peripheral surfaces, and insulating auxiliary cases 25 and 2 are open at the upper and inner ends on the discharge side, respectively.
6, respectively.

The above-mentioned auxiliary cases 25 and 26 are fixedly installed inside both ends of the shield case 27 which is open upward. At each end of both side walls 28 and 29 of this shield case 27, at positions corresponding to the auxiliary cases 25 and 26, there are notches 3.
1 and 32 are formed, respectively. The side walls 28a, 29a of the side walls 28, 29 formed by the notches 31, 32, and the auxiliary cases 25, 26
Gaps 33 and 34 are respectively formed by the inner ends. In FIG. 2, horizontal guides 35 are formed on both sides of the auxiliary case 25.
The upper part of the auxiliary case 25 is closed by an insulating cover 36 that can be detachably engaged with the guide 35. The other auxiliary case 26 is also closed by a similar insulating cover 36.

In this way, the upper surfaces of the insulating blocks 21 and 22 are made smaller, and their peripheral surfaces are replaced by the auxiliary case 2.
By separating the shield case 27 from the inner wall surfaces of the insulation blocks 21 and 26,
This reduces creeping leakage to the surface of the printer, eliminating problems such as copy omissions and machine malfunctions due to noise.

When aiming to increase the copying speed and extend the life of the photoconductor in a copying machine, ozone and discharge products (NO _x ) are generated as the corona current increases, resulting in deterioration of the photoconductor and partial white spots on copies. Such inconveniences may occur. To prevent this, air is vented from the bottom plate side of the charger as described above. As shown in FIG. 3, the above-mentioned gaps 33 and 34 are formed in the charger, so that when the above-mentioned suction is performed, air flows into the charger as shown by arrows 37 and 38. Due to this air flow, foreign matter 39 adheres to the discharge wire 7 in the vicinity of the insulating blocks 21 and 22, contaminating the discharge wire 7 and causing abnormal discharge.

FIG. 4 shows a charger that solves the above problem. In FIG. 5, the insulating cover 41 is similar to the above-mentioned insulating cover 36, and the auxiliary cases 25, 2
The auxiliary case 2 is guided by each guide 35 of 6.
5 and 26 can be closed off.
A closing portion 42 that can close the gaps 33 and 34 is formed at the inner end of the insulating cover 41, that is, at the end on the discharge side. This insulating cover 41
By attaching the to the auxiliary cases 25 and 26,
The gaps 33 and 34 are closed by a closing portion 42, as shown in FIG. 4, to prevent the discharge wire 7 from being contaminated.

When continuous copying was performed using the charger shown in FIG. 4, over 200,000 copies were made without any missing copies due to the above-mentioned abnormal discharge. The conventional charger shown in Figure 7 was tested under the same test conditions.
Compared to the case where copy omissions occurred before and after copying 10,000 copies, a significant improvement effect was confirmed with the charger of the present invention.

In the above embodiment, the present invention was applied to an air suction type charger, but even a charger equipped with a normal type shield has the same problem as described above due to the presence of corona wind. Therefore, the present invention can be effectively applied.

"Effects of the Invention" As explained above, according to the present invention, the insulating block supporting the discharge wire is provided separated from the inner wall of the insulating auxiliary case, and the auxiliary case corresponds to the shield case. Creepage leakage from the insulating block is reduced by providing notches at both ends of the shield case to form a gap between the inner edge of the auxiliary case and the side formed by the notches of the shield case. Various adverse effects that occur can be eliminated.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a charger showing an embodiment of the present invention, Fig. 2 is a perspective view of an auxiliary case and an insulating cover, Fig. 3 is a plan view of the charger, and Fig. 4 is a perspective view of the charger according to the present invention. FIG. 5 is a perspective view of an insulating cover applied to the charger shown in FIG. 4, FIG. 6 is a perspective view of a conventional charger, and FIG. 7 is a plan view of a conventional charger. , FIG. 8 is a longitudinal sectional view as well. 7... Discharge wire, 21, 22... Insulating block, 25, 26... Auxiliary case, 27... Shield case, 28, 29... Side wall, 33, 34...
Gap, 35...Guide, 36, 41...Insulating cover, 39...Foreign object, 42...Occluded portion.

Claims (1)

[Claims for Utility Model Registration] Each end of the discharge wire is hooked to an insulating block that supports the wire, and the upper and discharge sides are open to form a box shape, and the inner wall is a pair of insulating auxiliary cases in which an insulating block is installed spaced apart from each side of the insulating block; a shield case having a notch formed at an appropriate distance from the inner end of the auxiliary case at a position facing the side wall of the auxiliary case at both ends of the side wall; and a shield case for closing the upper part of the auxiliary case. and an insulating cover detachably attached to the auxiliary case.