JPH0454412Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention mainly relates to a sensor for detecting the remaining amount of toner in a copying machine.

2. Description of the Related Art As shown in FIG. 4, a conventional toner remaining amount sensor utilizes a unimorph type vibrator 5 provided facing inside the side wall of a toner tank 4.

The principle of this sensor is as shown in FIG.
The toner is self-oscillated when supported by the toner, and the oscillation stops due to mechanical damping due to the contact load with the toner.The oscillation when the toner runs out is extracted as an electrical output to detect the remaining amount of toner. That's what I do.

Here, the periphery of the metal plate 5b of the unimorph type vibrator 5 is supported by the casing 1 so as to be flush with the inner surface of the toner tank 4, as shown in FIG. The reason why the metal plate 5b is made flush with the inner surface of the toner tank 4 is that the vibration of the metal plate is suppressed by the adhesion of fine powder toner, and as a result,
This is to prevent malfunctions in which it is reported that there is no toner remaining when there is no remaining amount.

Problems to be Solved by the Invention Incidentally, the above-described unimorph type vibrator 5 generates bending vibration when voltage is applied, but the node line of the vibration mode is located at the metal plate 5b of the vibrator.
Since the metal plate 5b is located slightly inside the periphery of the metal plate 5b, if a structure is adopted in which the periphery of the metal plate 5b is supported by the casing, vibrations will be suppressed and vibrations will leak through the casing and the toner tank. It turns out.

In order to solve this problem, conventionally, as shown in FIG. 5, a heavy metal ring 9 is provided as additional mass on the casing 1 near the periphery of the metal plate.
Alternatively, the casing 1 itself is made of heavy die-casting material, but all these methods are used to prevent vibration leakage by suppressing vibrations, and such means cannot increase the detection sensitivity of the remaining amount of toner. , it is undeniable that the cost increases due to the provision of additional mass.

Means for Solving the Problems The present invention has a unimorph type vibrator mounted on the toner tank flush with the inner surface of the toner tank.
It is an object of the present invention to provide a toner remaining amount sensor with high detection sensitivity without suppressing the vibration of the vibrator.

To achieve the above object, the present invention provides a toner remaining amount sensor using a unimorph type vibrator having a piezoelectric ceramic on one side of a metal plate, the metal plate having a dish portion to accommodate the piezoelectric ceramic. of,
Along with forming a bend along the node line,
The sensor is characterized in that a bent portion on the outer surface of the dish portion is supported by the sensor casing.

Effect As mentioned above, the part that becomes the node line of the metal plate of the unimorph type vibrator is made into a dish-shaped bent part,
By supporting the metal plate on the casing at this portion, it is possible to fix the metal plate to the casing without suppressing the vibration of the metal plate, thereby preventing vibration leakage. At the same time, since the dish-shaped bent portion is supported by the casing, the metal plate and the inner surface of the toner tank can be formed flush with each other while maintaining good airtightness. There is no unevenness formed between the two, and therefore,
This eliminates detection errors due to load fluctuations due to toner adhesion.

Embodiment As shown in FIG.
is incorporated. The portion of the casing 1 located on the inner surface of the toner tank 4 (see FIG. 4) is
An opening is formed for attaching the metal plate 5b of the unimorph type vibrator 5. A silicone rubber 6 is interposed between the unimorph type vibrator 5 and the opening of the casing 1, so that the vibrator 5, the casing 1, and the inner surface of the toner tank are flush with each other. ing. As shown in FIG. 2, the unimorph type vibrator 5 is composed of a piezoelectric ceramic 5a and a metal plate 5b, and the metal plate 5b is bent into a dish shape at the portion where the node line is located. The piezoelectric ceramic 5a is bonded to the recessed portion inside the bent portion 5e.

5c is an input electrode, and 5d is an output electrode. Note that various patterns may be used for the arrangement of the input/output electrodes, and the piezoelectric ceramic itself may be a known one, such as PZT. 7 in FIG. 1 indicates the input electrode 5c and the metal plate 5.
8 is a lead wire connected to the output electrode 5d, from which vibration output is extracted.

Effects of the invention Since the toner remaining amount sensor according to the invention is configured as described above, the metal plate can be provided flush with the inner surface of the toner tank without suppressing the vibration of the unimorph type vibrator, and as a result, the detection sensitivity The present invention has excellent effects such as being able to prevent detection errors caused by toner adhesion, as well as being able to omit conventional parts such as metal rings, thereby reducing manufacturing costs.

In addition, since the node line of the metal plate is supported by the casing, the oscillation of the unimorph type vibrator is stabilized, and the oscillation circuit itself can be made simple.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a toner remaining amount sensor as an embodiment of the present invention, FIG. 2 is a plan view of a unimorph type vibrator, and FIG. 3 is a cross-sectional view of FIG.
FIG. 4 is a diagram showing a toner tank to which a remaining toner amount sensor is applied, and FIG. 5 is a sectional view showing a conventional remaining toner amount sensor. 1...Sensor casing, 5a...Piezoelectric ceramic, 5b...Metal plate.

Claims (1)

[Claims for Utility Model Registration] (1) A toner remaining amount sensor using a unimorph type vibrator in which a piezoelectric ceramic is provided on one side of a metal plate, wherein the piezoelectric ceramic is housed in a toner remaining amount sensor.
A remaining toner amount sensor, characterized in that a plate portion is formed on the metal plate to be bent along the node line, and the bent portion on the outer surface of the plate portion is supported by a sensor casing. (2) The remaining toner amount sensor according to claim 1, wherein silicone rubber is interposed in the gap between the bent portion and the sensor casing.