JPS5815726B2 - Ekimen Level Kenshiyutsu Sochi - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid level detection device.

Conventionally, in order to detect the liquid level, a so-called float switch has been used, in which a float is floated on the liquid surface and the switch is opened and closed by the vertical movement of this float. A pump P supplies the developer 2 in the liquid tank 1 at a timely manner to the developer tray 4.
, the electrostatic latent image formed on the surface of the photosensitive drum 6 is visualized by supplying it to a cleaning blade 5 or the like, or an unnecessary image after the transfer is removed.
Therefore, if the above-mentioned float switch is used in an electrophotographic copying machine in which the developer 2 is circulated by returning excess liquid to the liquid tank, a problem occurs in the operation of the switch.

In other words, since there is a difference between the liquid level B in the liquid tank when the pump P is activated and the liquid level A in the liquid tank when the pump P is stopped, the detection operation of the float switch is at the above level. This is sometimes carried out at level C, which is between level A and level B. Therefore, even if the liquid level falls below level C and the float switch detects when pump P is operating, pump P is stopped. Then, since the liquid level becomes equal to or higher than level C, the once activated float switch is deactivated again, and the liquid level cannot be properly detected.

An object of the present invention is to provide a liquid level detection device that eliminates the above-mentioned problems.

Tank 8 according to the invention shown in FIGS. 2 and 3
As shown in FIG. 2, the tank 8 is screwed or glued (
As shown in FIG. 3, this tank 8 has an opening 8a located below the tank chamber 8A, and an exhaust port 8b at the top. are provided for each.

- In the tank chamber 8A of the tank 8, a supply pipe (indicated by a two-dot chain line in FIG. 2) connected to the pump P attached to the liquid tank 1 is arranged so as to pass through the opening 8a of the tank 8. ing.

In addition, the open end of the supply pipe is the tank chamber 8A in FIG.
The opening is positioned so that it is exposed above the liquid level, so that the liquid flowing out from the opening is not subjected to resistance from the stored liquid during liquid supply.

On the other hand, in the upper part of the tank 8, a detector 12 is provided in which a float 9 floating on the liquid surface in the tank chamber is connected to an actuator of a switch 111 by a connecting rod 10.

The detection device configured as described above detects the remaining amount in the liquid tank based on the movement of the float 9.

That is, the opening 8a of the tank 8 is located below the tank chamber 8A, the exhaust port 8b of the tank 8 is sealed, and the inside of the tank chamber is made airtight. When the opening 8a is exposed at a level C6 or lower,
When the liquid in the tank chamber flows out and the float 9 drops,
The detection operation of the detector 12 is performed.

According to this device, when the liquid in the tank chamber 8A falls below level C8, it flows out and at the same time air enters the tank chamber. Even if the liquid level becomes equal to or higher than level C6 again due to liquid circulation, the float 9 remains lowered because the liquid cannot enter the tank chamber 8A.

Therefore, the liquid level in the liquid tank is once level C.
Even if the level drops to below C6 and rises again to level C6 or higher, the detection operation of the detector 12 will not be affected by the level change.

Furthermore, even if the liquid level in the liquid tank is undulated due to liquid circulation, the liquid level in the tank chamber 8A is not affected by this, so the detector 12 will not malfunction due to the undulation.

As mentioned above, a detection device that does not change once the liquid level in the tank chamber changes is used when replenishing the liquid.
The exhaust port 8b provided at the top of the tank 8 is opened to communicate the indoor and outdoor areas of the tank so that the air inside the tank can be discharged, so that when the supply pump P is operated, the air flows out from the opening of the supply pipe. Replenishment fluid can be stored.

Also, instead of opening the tank exhaust port 8b appropriately as described above, as shown in Fig. 4, the pipe ■a of the valve ■ is inserted into the exhaust port 8b, and the liquid is refilled. For example, when the replenishment pump is activated, the valve (2) may be opened in conjunction with the operation of the replenishment pump.

Next, an example will be described with reference to FIG. 5, in which the exhaust port 8b in the upper part of the tank 8 is provided with an exhaust valve that opens in the direction of exhausting the air in the tank chamber 8A.

In FIG. 5, an exhaust port 8b of the tank 8 is provided with an exhaust valve 13 that is opened in a direction to exhaust the air in the tank chamber 8A.

When such an exhaust valve 13 is provided, the tank chamber 8A and the outside of the tank chamber are communicated through the opening 8a of the tank 8, so that as the liquid level outside the tank chamber rises, the tank chamber 8A is The liquid level will also rise.

Therefore, while the detector is activated by the liquid level in the tank chamber 8A, the liquid level A in the tank chamber 8A when the detector 12 is not activated.

and the liquid level B in the tank chamber 8A when the detector 12 is activated.

MH6 is the level A of the liquid in the liquid tank 1 containing the returning liquid etc. when the liquid is not delivered and the liquid level A in the liquid tank 1 when the liquid is delivered.
If the activation timing is set so that the level difference H between the liquid level B and the liquid level inside the tank chamber 8A is greater than the level difference H, the activation of the detector 12 will be based on the level due to liquid supply or non-supply in the liquid tank outside the tank chamber 8A. It will not be canceled within the range of fluctuation.

That is, when the liquid level outside the tank chamber rises due to liquid replenishment or liquid returning to the liquid tank 1, the air in the tank chamber 8A is exhausted via the exhaust valve 13; The surface level also increases.

On the other hand, even if the liquid level outside the tank decreases due to liquid supply to the developing tray or cleaning blade, the exhaust valve 1
3 is closed, the liquid level in the tank chamber 8A does not drop.

However, due to liquid supply, the liquid level outside the tank room was lowered to the tank 8.
When the level drops below the level at which the opening 8a is exposed, the liquid in the tank chamber 8A flows out into the liquid tank 1 through the opening 8a, and as a result, the liquid level in the tank chamber 8A decreases.

; At this time, the float 9 of the detector 12 is also in the tank chamber 8A.
The detection operation is performed at the liquid level Bo.

At the point when this detection operation is completed, even if the liquid level outside the tank room increases by the level difference H between the supply and non-supply of liquid, the level difference H6 with respect to the detector activation timing is greater than this level difference H. Since this is large, the detector is not deactivated and the detection position is maintained.

As described above, when an exhaust valve that has the habit of opening in the direction ν for discharging the air in the tank chamber is provided, even if there is a difference in the liquid level in the liquid tank between when the liquid is being supplied and when it is not being supplied. , the liquid level in the tank chamber can be properly detected.

Note that by connecting the exhaust valve 13 and the exhaust port 8b with a pipe (not shown), the exhaust valve 13 can be installed at a location where inspection and maintenance are easy or where dust is difficult to enter.

Note that the above-mentioned detector may use a photoelectric conversion element and a light source device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a device in which a detection device according to the present invention is used, FIG. 2 is a diagram showing a state in which an embodiment of the detection device according to the present invention is used, and FIG. FIG. 4 is a perspective view of the detection device shown in FIG. 2, FIG. 4 is a partially modified example of the detection device shown in FIG. 2, and FIG. FIG. 8...tank, 8a...opening, 8A...tank chamber, 12...detector, 8b...exhaust port, 13...exhaust valve.

Claims (1)

[Claims] 1. An opening that is placed immersed in a liquid tank, is sealed with the liquid in the liquid tank, and is opened by the liquid level when the liquid level in the liquid tank falls below a predetermined level. A tank having an exhaust part on the upper part, a detector for detecting liquid level displacement in the tank chamber, and a detector provided in communication with the exhaust part of the tank, and a detector for detecting the liquid level displacement in the tank chamber, A liquid level detection device having a member that releases air inside the tank to the outside of the tank.