JPS59202472A - Device for detecting toner replenishing time for copying machine - Google Patents

Abstract

PURPOSE:To ensure generation of a toner replenishment demand signal and to prevent misdetection of replenishment time by displaying the remaining amt. of toner in accordance with an amt. of strain of the thin elastic plate applied to the opening of the surrounding wall of a toner tank. CONSTITUTION:The bottom wall 31a of the casing 31 of a toner replenishment time detector 30 faces the opening part 11b of a toner tank 11 and its flange 31e is fixed with screws 32. A thin elastic silicone film 33 is stuck to an annular adapter 34 at the opening part 31b of the casing 31. The film 33 is bent with a pressure due to an actual remaining amt. of toner. The pressure due to the remaining amt. of toner is in proportional relationship to an amt. of bending. A strain gauge of a semiconductor is attached to the strained part of the film 33. An amt. of remaining toner is detected with a value obtained by this gauge.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying machine, and more particularly to a toner replenishment timing detection device for a copying machine suitable for detecting the timing of replenishment of developing toner stored in a toner tank of a copying machine.

Conventionally, this type of toner replenishment timing detection device includes, for example, a ceramic vibrator attached to a part of the peripheral wall of the toner tank, and a ceramic vibrator that responds to changes in the actual amount of toner remaining in the toner tank. Some devices use changes in the oscillation phenomenon of the toner to detect when toner is to be refilled into the toner tank.

However, in such a configuration, the mounting conditions of the ceramic vibrator to the toner tank are delicate;
It is difficult to mount the ceramic vibrator to the toner tank in a manner that meets these mounting conditions, and as a result, there is a high degree of erroneous detection of toner replenishment timing.

The present invention was made in response to such problems,
The purpose of this is to replenish toner for copying machines by effectively utilizing the function of a strain gauge, focusing on the fact that developing toner is made up of many fine particles that can be considered a liquid. An object of the present invention is to provide a timing detection device.

In order to achieve such an object, the present invention has a structural feature9 in which, in a copying machine equipped with a toner tank storing developing toner, the toner is stored at a surface level corresponding to the allowable remaining amount of the toner. An opening is formed in the peripheral wall of the tank, and an elastic thin film is fixed to the opening so as to seal the opening and bends under pressure due to the actual remaining amount of toner, and the elastic thin film is provided with an elastic thin film. This causes strain in accordance with the amount of deflection of the elastic thin film, and the amount of strain is
a strain gauge that generates a detection signal representing the actual remaining amount; a reference signal generating means that generates the allowable remaining amount as a reference signal; The present invention also includes a replenishment request signal generating means for generating a replenishment request signal indicating that toner needs to be replenished.

However, by configuring the present invention in this way,
The pressure that the toner exerts on the inner circumferential surface of the toner tank with its actual remaining amount in substantially the same way as a liquid is always accurately determined as the deflection pattern of the elastic thin film, that is, the amount of strain on the semiconductor strain gauge. Therefore, when the remaining amount of toner corresponding to the amount of distortion is reduced by the allowable remaining amount, the replenishment request signal can be reliably generated, and as a result, the toner replenishment time can be erroneously detected. do not have.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
2 and 2 show a state in which a toner replenishment timing detection device 60 according to the present invention is attached to a toner tank 10 of a copying machine. The toner tank 10 stores developing toner 20 in the tank body 11 and also stores the developing toner 20 in the tank body 11.
The supply port 11a is connected to the lid body 12! An opening 11b is formed in the peripheral wall of the tank body 11 in the vicinity of a surface level representing the allowable remaining amount of toner 20. Note that reference numeral 11c indicates a supply port for toner 20 to the developing device of the copying machine.

The toner replenishment timing detection device 60 has a casing 61 formed of a synthetic resin material, and this casing 3
1 is assembled by overlapping the bottom wall 61a with the peripheral wall of the tank body 11 at a position corresponding to the opening 111) and tightening the flange portion 31e with screws 62-62. An opening 61b that overlaps the opening 11b of the tank body 11 is formed in the center of the bottom wall 61a of the casing 61, and an elastic thin film 66 made of silicon is formed in the opening 31b so that its strain The part 66a (see FIG. 6) is exposed inside the tank body 11 through both openings 31b and 11b, and the outer peripheral edge part 33b is attached by pasting with an annular adapter 64 (made of a synthetic resin material). There is. As a result, the strain-generating portion 66tl of the elastic thin film 66 is bent due to the pressure angle caused by the actual remaining amount of the toner 20. In this case, the pressure due to the actual remaining amount of toner 20 and the amount of deflection of the strain-generating portion 33a are in a proportional relationship to each other.

As shown in FIG. 6, a pair of semiconductor strain gauges are provided on the surface of the strain-generating portion 33a of the elastic thin film 36. , +f2 are attached, and each of these semiconductor strain gauges f1°? -2 is strain generating part 6
Distortion occurs in accordance with the deflection of 6a.

In this case, the amount of strain in each semiconductor strain gauge fj1 + lz is proportional to the amount of deflection of the strain generating portion 66a. The circuit board 65 is assembled to the annular peripheral wall part 31C of the casing 61 with its outer peripheral part held by annular stoppers 31d and 31(i). A circuit section 66 that constitutes a circuit is provided.

The circuit section 66 includes a variable resistor 36a and a fixed resistor 36 that form a bridge circuit G together with the semiconductor strain gauges 2□, 2□.
1), a DC voltage from a voltage regulator 36c is applied between the surface input terminals of the bridge circuit G. The voltage regulator 36c is composed of a variable resistor, and divides the supply voltage OO from the DC power source to generate the DC voltage. Therefore, the variable resistor 36a and the voltage regulator 66C are adjusted so that when the amount of toner 20 in the toner tank 10 is full, the detected voltage generated between both output terminals of the bridge circuit G becomes zero. . The operational amplifier 36d amplifies the detected voltage from the bridge circuit G and applies the amplified voltage to the filter 6e. Filter 3
Reference numeral 6e includes a resistor and a capacitor, and removes electrical noise caused by mechanical vibration of the toner tank 10 from the amplified voltage to generate a filter voltage.

The comparator 36h is connected to a reference voltage generator consisting of filters 36e and 36o: a fixed resistor 66f and a variable resistor 66t connected in series, and the variable resistor 662 cooperates with the fixed resistor 36f to Power supply voltage from DC power source■. 0 is divided and generated as a reference voltage. In this case, the reference voltage represents the allowable remaining amount of the toner 20 described above. The comparator 56h generates a high level signal when the filter voltage from the filter 66e is higher than the reference voltage from the reference voltage generator, and eliminates the high level signal (i) when the filter voltage is lower than the reference voltage. The transistor 56i becomes conductive in response to the high level signal from the comparator 36h, generates from its collector a replenishment request signal indicating that the toner 20 needs to be replenished, and responds to the disappearance of the high level signal. Then, it becomes non-conductive and eliminates the replenishment request signal.

In this embodiment configured as described above, when the actual remaining amount of toner 2[l in the toner tank 10 decreases and becomes less than the allowable remaining amount, the elastic thin film 66
The amount of deflection of the strain-generating portion 33a of each semiconductor strain gauge decreases.
. In this case, the detected voltage corresponds to the actual remaining amount of the 1-ner 20 that is less than or equal to the allowable remaining amount. Next, the operational amplifier 36 (1) amplifies the detected voltage from the bridge circuit G and generates an amplified voltage, and in response, the fill 36e generates a filter voltage. , 6e from the reference voltage generator and generates a high level signal based on the fact that the filter voltage is higher than the reference voltage, and in response, transistor 661 generates a replenishment request signal through its conduction.
It is possible to know that it is time to replenish the toner 20 into the toner tank 10.

In such a case, since the toner 20 is composed of a large number of fine particles,
This decreasing state of the l·ner 20 is substantially the same as that of the liquid. In other words, the strain-generating portion 66 of the elastic thin film 66
Since the pressure applied to a decreases in proportion to the decrease in toner 20, the amount of deflection of the strain generating portion 33a, that is, the amount of deflection of the semiconductor strain gauge 11
The amount of distortion of +19-2 decreases in proportion to the decrease in toner 20, and accordingly, the detection voltage from the bridge circuit G increases in inverse proportion with accuracy, and as a result, the timing for replenishing toner ~20 decreases. can always be detected correctly.

In the above embodiment, the bridge circuit G is constructed using both semiconductor strain gauges g++, ? We have explained an example in which z is used, but instead of this, is it possible to use both semiconductor strain gauges? One of l+ #2 may be replaced with a fixed resistor, and in such a case, the bridge circuit G may be a half-bridge circuit.

Further, in the embodiment, the strain-generating portion 3 of the elastic thin film 66
Each semiconductor strain gauge in 15a? 1 + #2 was explained, but instead of this, each semiconductor strain gauge l
x + #2 may be formed integrally with the elastic thin film 66 by vapor deposition.

Further, in the above embodiment, an example was explained in which the device of the present invention is attached to the peripheral wall of the tank body 11, but instead of this, the device of the present invention may be attached to the inclined bottom wall of the tank body 11. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the device of the present invention attached to the peripheral wall of a toner tank, FIG. 2 is an enlarged sectional view of the device of the present invention, and FIG. 6 is a view of the strain-generating portion of the elastic thin film in FIG. The enlarged view, FIG. 4, is the circuit configuration diagram of the circuit section in FIG.
The figure shows the device of the present invention attached to the inclined bottom wall of the toner tank. Explanation of symbols 10... Toner tank, 11... Tank body-11
1b...Opening portion, 20...Toner, 63...Elastic thin film, 36f...Fixed resistance, 662...Variable resistance,
3.4) h...Comparator, 36i...Transinutor, #1+f2...Semiconductor strain gauge. Applicant Nippondenso Co., Ltd. Agent Patent Attorney Teru Hase - /3 (□3) m: Figure 3 Figure 4 F Figure 2 6

Claims (1)

[Claims] In a copying machine equipped with a toner tank storing developing toner, an opening is formed in a peripheral wall portion of the toner tank corresponding to a surface level representing an allowable remaining amount of the toner, and the opening is sealed tightly. an elastic thin film that is fixed to the toner so that it bends under pressure due to the actual remaining amount of the toner; , a strain gauge that generates a detection signal representing the actual remaining amount; a reference signal generating means that generates the allowable remaining amount as a reference signal; and when the value of the detection signal becomes smaller than the value of the reference signal. A toner replenishment timing detection device for a copying machine, comprising a replenishment request signal generating means for generating a replenishment request signal indicating that the toner needs to be replenished.