JPS5825683A - Grounding structure for photosensitive drum - Google Patents

Abstract

PURPOSE:To perform speedy inspection and recovery regarding the photosensitive drum of an electrophotographic copying machine, etc., only by inserting the measuring probe of a measuring instrument into a prescribed socket, and thus automatically insulating the photosensitive drum from the machine frame. CONSTITUTION:A photosensitive drum 14 is grounded normally through supporters 13A and 13B, a center shaft 12, a bearing 11B, an electric conductor 16, a fitting screw 17, a contact spring 24, and a fixation-side contact 23. When a measuring probe A is inserted into a socket 20 for the inspection of a corona discharger 15, the contact spring and fixation-side contact are pressed to open at the tip part of the measuring probe, and the photosensitive drum 14 is ungrounded. Therefore, the measurement and recovery and performed only by inserting and extracting the measuring probe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for selectively grounding a photoreceptor drum of an electrophotographic copying machine or the like to the machine body and easily measuring the charged potential on the surface of the photoreceptor drum.

As is well known, in electrophotographic copying machines, charging electrodes,
Transfer/separation electrodes excluded! Various types of corona dischargers such as electrodes are used, but when maintaining the copying machine, it is important to check whether the electrode wires of the corona discharger are broken, whether the applied voltage is appropriate, and whether the selenium photosensitive material formed on the surface of the photoreceptor drum, etc. The current flowing from the corona discharger to the photoreceptor drum may be measured for the purpose of inspecting the quality of the body and the relationship between the electrode wires.

To perform this measurement, first insulate the photoreceptor drum and the aircraft body, and measure the current flowing between the photoreceptor drum and the aircraft body using a tester, etc. while applying a specified voltage to the corona discharger. is normal.

However, under normal conditions, the photoconductor drum must be grounded to the aircraft body, so current measurements are performed by replacing the photoconductor drum with a dummy drum that can be insulated from the aircraft body. Installing a dummy drum every time requires a great deal of time and effort. Furthermore, the photosensitive portion may be damaged when replacing the photosensitive drum.

For this reason, a supporting structure for a photosensitive drum as shown in FIG. 1 has conventionally been proposed for the purpose of the above-mentioned current measurement. That is, in FIG. 1, the symbols /A and /B are the fuselage frame, λ is the corona discharger, and 3 is the photoreceptor drum.
Group A and Group B are supporters, and both supporters lIA,1
1. Electric insulators 4A and 4B are interposed between B and the left side of the center axis. A metal connecting screw 7 is screwed into the converter +B, which is divided into λ pieces as divided pieces 4a, &b, and the photosensitive drum 3 is connected to the fuselage frame /A, /BVc via this connecting screw 7. be done. Therefore, when inspecting the corona discharger, simply by removing the connecting screw 7, the photosensitive drum 3 and the body frames /A, /B can be easily insulated. However, with such a structure, a special support structure must be adopted just for inspection purposes, which increases the product cost, and the connecting screw 7 is attached and detached from outside the machine. There is a risk that it will take a long time to complete the process or that the connecting screw 7 may fall into the machine.

In order to solve the above-mentioned problems in inspecting corona dischargers, the present invention has been developed by simply inserting the measuring probe of the measuring device into a predetermined socket while the photosensitive drum is normally grounded to the aircraft body. This paper proposes a structure that automatically insulates the space between the photoreceptor drum and the machine body.

Although an example in which the entire fuselage frame is made of an electrically insulating material will be described below with reference to the drawings, in the present invention, a part of the fuselage may be made of an electrically insulating material.

In Figure 1, 10Bk:
L K made of electrically insulating material, both fuselage #)A, 10
A metal central shaft is rotatably supported by the bearings //A and //B of B, and a cylindrical shaft is connected to this central shaft through a pair of metal supports /3k and /3B. The photoreceptor drum is supported by a blowfish. Also, the aircraft 10k.

10B, I, and 11K are corona dischargers/left facing the circumferential surface/Fa of the photoreceptor drum.

According to the present invention, a bearing //B is provided on the surface of the body 10H.
An electrical conductor/B is installed. This electric conductor /A is shown in the third diagram, with one end /AeL bearing //B
It is tightly attached to the outer race of the body 10B and fixed to the mounting hole /g of the fuselage body 10B with a metal mounting screw /7. Electrical conductor/
A measurement probe A is shown by a phantom line in the singing section of A/Ab.
A socket θ having an opening /q into which can be inserted is fixed, and a through hole U/ coaxial with the opening /9 is bored in the corresponding part of the body 10H.

On the other hand, a fixed side contact 23 grounded with two lead wires is fixed to the inner surface of the fuselage body 10B closest to the through hole 2/K, and this fixed side contact 23VC cannot be brought into contact with the tip cog a of the contact spring cog. be. The base λpb of the contact spring cog is attached to the fuselage 1 by the Naratoco 3 screwed into the mounting screw/7.
At the same time as being fixed at 0B, the electrical conductor /,! , V
The intermediate portion 2'lc of the contact spring cog is opposed to the inner end of the through hole 2/.

Since the above-described embodiment has the above-described configuration, normally the photosensitive drum 11 is the supporter/3A.

/3B, central axis /, 2, bearing //B, electric conductor /6, mounting screw /7, contact spring, 21I, grounded via fixed side contact 3. When the measurement probe A is inserted into the socket l-, 20 during the inspection of the corona discharger ls,
As shown by the phantom line in FIG. 3, the distance between the contact spring cog and the fixed side contact cog 3 is pushed open at the tip of the measurement probe A5-, thereby insulating the photosensitive drum lg and the ground. Therefore, measurement and restoration can be performed only by inserting and removing the measurement probe A.

After all, the grounding structure according to the present invention can be realized by slight improvements to the aircraft frame and the addition of small parts, so it can be implemented at low cost, and when inspection is necessary, it can be quickly inspected and restored by simply inserting and removing it from the measuring probe. This has the advantage of making maintenance work easier.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional grounding structure, FIG. 1 is an overall sectional view of the grounding structure for a photosensitive drum according to the present invention, and FIG. 3 is an enlarged sectional view of the main parts of the same structure. ioh, ioB...aircraft, //A, //B・
・・Bearing, /2・・Center shaft, /Da・・Photosensitive drum, 16・・Electric conductor, /7・・Mounting screw, 20・−
Socket 1.23... Fixed side contact 5.2 G... Contact spring, A... Measurement probe. 6-

Claims (1)

[Claims] 1) In a photoconductor drum that is always grounded to the machine body and electrically insulated from the machine body during electrical characteristics inspection, an electrical conductor that is electrically connected to the photoconductor drum through a receiving member of the photoconductor drum. and a conductive member connected to the electric conductor and grounded to the aircraft body, and when the measuring member is inserted, the measuring member and the electric conductor come into contact and a part of the electric conductor is separated from the conductive member. The grounding structure of the photoreceptor drum is characterized by: