JPS6052349A - Liquid level detection alarm - Google Patents

Abstract

PURPOSE:To achieve a cost reduction and a smaller size of an inkjet recorder or the like by a method wherein an alarm is outputted when the liquid level in a tank is below the specified value while a different alarm is outputted when the liquid level therein is below the specified value even after the action of supplying a liquid to the tank according to the former alarm. CONSTITUTION:The resistance Rx between electrode pairs 9 becomes infinite when the position of the ink liquid surface in a sub ink tank 4 is lower than the electrode pairs 9. An intermittent signal P2 is introduced to the base of a transistor T2, which is turned ON or OFF intermittently while a LED23 is flashed intermittently. When a working switch 15a of a pump 15 is turned ON to perform a forced supply of ink to the sub ink tank 4 with a suction cap 16 according to the alarm, a continuous high level output of an NAND gate 26 is introduced to the base of the transistor T2 to light the LED23 continuously. But when the main ink tank 12 runs out of ink, the lighting of the LED23 continues.

Description

Detailed Description of the Invention Technical Field The present invention relates to a liquid volume detection and alarm device, and in particular to a liquid volume detection and alarm device used in an inkjet recording device, etc., which detects the volume of liquid stored in a tank and issues an alarm based on the detection result. The present invention relates to a detection alarm device.

Conventional technology In an inkjet recording device that performs dot recording by ejecting ink as droplets, there is a sub-ink tank that is directly connected to a nozzle for ejecting ink droplets and is placed near the nozzle, and a sub-ink tank that is arranged near the nozzle to eject the ink droplets. An air layer is provided inside the main tank for storage to absorb internal ink pressure fluctuations caused by movement of the tank during recording operations. As ink droplets are ejected from the nozzles during the recording operation, the same amount of ink as the ejected amount is sequentially supplied from the main ink tank to the sub-ink tank.

With this configuration, when the main ink tank becomes empty, the ink in the sub ink tank naturally decreases with the recording operation, resulting in an ink shortage, but there is a sufficient amount of ink in the main ink tank. Even if there is ink present in the sub-ink tank, the amount of ink stored in the sub-ink tank may decrease and ink may run out.

For example, if the recording device is left unused for a long time or the outside temperature fluctuates rapidly, the air dissolved in the ink in the sub-ink tank may be removed from the ink, or the sub-ink tank and Air enters the sub-ink tank from the connection with the ink supply pipe, increasing the air layer, thereby reducing the amount of ink in the sub-ink tank.

In this case, it is necessary to remove air from the sub-ink tank and to forcibly supply ink from the main ink tank to the sub-ink tank.

Therefore, it is necessary to distinguish between running out of ink due to a decrease in the amount of ink in the main ink tank and running out of ink due to a decrease in the amount of ink only in the sub-ink tank.

For this purpose, an ink amount detection/alarm device is used that detects the ink amount in both tanks and issues an alarm based on the detection results. In order to perform this separately, a liquid amount detection means is provided for each tank, and an alarm means is also provided separately for each tank, so that detection and alarm are performed separately for each tank.

However, in such a configuration, since a plurality of detection means and a plurality of alarm means are provided, the cost of the entire inkjet recording apparatus increases and the space occupied by the alarm means and the like becomes large.

The above drawbacks are not limited to the ink amount detection and alarm devices of the above-mentioned inkjet recording device, but also apply to liquid amount detection and alarm devices of multiple tanks connected so that one of them supplies stored liquid to the other in equipment that uses other liquids. This applies to all liquid level detection and alarm devices that separately issue alarms for each tank based on detection results.

Purpose The present invention has been made in view of the above circumstances, and is a method of detecting the liquid level of each tank and issuing an alarm based on the detection result using a single detection means and alarm means in the above-mentioned type of liquid level detection and alarm device. It is an object of the present invention to provide a liquid level detection/alarm device that can be used to distinguish liquid levels and reduce the cost and size of the entire device in which it is installed.

EXAMPLES The present invention will be described in detail below based on examples shown in the drawings. In this case, an ink amount detection alarm device used in an inkjet recording apparatus will be taken as an example.

FIG. 1 shows the main configuration of an inkjet recording apparatus to which the apparatus of the present invention is applied.

The carriage 2 is provided on a carriage 2 which is slidably provided on the carriage 3. Also, the ink I is placed behind the nozzle on the carriage 2.
A sub-ink tank 4 in which ink is stored is provided. The sub-ink tank 4 is made of a rigid material and has a sealed structure, and a rear part of a supply pipe 5 for supplying ink whose tip is connected to the rear end of the nozzle 1 is disposed inside the tank.

The rear end of the supply pipe 5 is bent toward the bottom of the sub-ink tank 4, and is immersed in the ink I in the sub-ink tank 4, and a filter 6 is fitted at its tip.

The filter 6 prevents foreign matter such as dust and bubbles in the ink I from entering the nozzle 1, and also prevents the ink 1 in the sub-ink tank 4 caused by the inertia of movement of the supply tube 10, which will be described later, during the recording operation. It also plays a role in absorbing pressure increases.

Further, the rear end portion of the atmospheric communication pipe 7 is exposed to the upper part of the interior of the sub-ink tank 4. The atmosphere communication tube 7 is formed as a straight glass thin tube having a diameter of 100 μm to 400 μm, and its tip faces above the tip of the nozzle 1. A predetermined amount or more of air pipes 8 are secured in the upper part of the sub-ink tank 4 via this atmosphere communication pipe 7. When the liquid level of the ink (■) in the sub-ink tank 4 attempts to rise above the atmosphere communication pipe 8, the air layer 8 inside the sub-ink tank 4 is completely sealed by the ink entering the atmosphere communication pipe 8. The air layer 8 will not decrease further. This air layer 8, like the filter 6 described above, plays the role of absorbing the ink pressure within the sub-ink tank 4 during the recording operation.

Furthermore, an electrode pair 9 is provided on the inner wall surface of the sub-ink tank 4 as an ink amount detection means of the ink amount detection and alarm device according to the present invention. It is connected. The height of the arrangement of the electrode pair 9 is such that when the ink level drops to that level during the alarm operation, the filter 6 is exposed from the ink I due to the vibration of the ink in the tank, and from there the air flows into the nozzle 1. will invade, so these should be taken into consideration when selecting the appropriate location.

A supply tube 10 for ink supply is connected to the above sub-ink tank 4, and this supply tube 1
A hollow burr 11 is connected to the tip of 0, and this hollow burr 1
1 is inserted into a rubber stopper 14 of the main ink tank 12 which is connected to a bag-shaped ink container 13 provided inside the main ink tank 12 . .

On the other hand, the reference numeral 15 in the figure is a pump for forcibly supplying ink (2) from the main ink tank 12 to the sub ink tank 4 when an alarm is issued that the amount of ink in the sub ink tank 4 has decreased. A suction cap 16 is connected to the pump 15 to the device.

With the above configuration, during recording, the carriage 2 is caused to run on the guide shaft 3 by a drive means (not shown), and the nozzle 1 is driven to deposit ink droplets onto a recording paper (not shown) placed opposite to the nozzle 1. Dot recording is performed by spraying. In this case, the ink ■ in the sub-ink tank 4 is consumed, but ~ the same amount of ink as the consumed amount is transferred from the ink container 13 of the main ink tank 12 to the rubber stopper 14.
The ink is sequentially supplied to the sub-ink tank 4 via the hollow needle 11 and the supply tube 10.

As mentioned earlier, when the device is left unused for a long period of time or when the outside temperature fluctuates rapidly, the air layer 8 inside the sub-ink tank 4 increases, and the liquid level of the ink ■ in the tank becomes low. . When the ink level becomes lower than the electrode pair 9, an ink amount detection and alarm device, which will be described later, detects this and issues an alarm.

In response to this alarm, ink is forcibly supplied to the sub-ink tank 4. In that case, in FIG. 1, the suction camp 16 is driven by a driving means (not shown), and is fitted into the nozzle 1 and the tip of the atmosphere communication pipe 7. Thereafter, the pump 15 is activated by turning on the activation switch 15a either automatically or manually, and suction is performed.

Due to this suction negative pressure, the air in the air layer 8 in the sub-ink tank 4 is sucked out through the atmosphere communication pipe 7, and the ink I corresponding to the amount is supplied to the main ink tank 12 through the supply tube 10. At this time, the ink I is also sucked from the nozzle 1 and the ink is secured in the nozzle 1. however,
Due to this suction, the ink liquid level in the ink tank 4 rises, and when the height exceeds the electrode pair 9 and reaches the atmosphere communication pipe 7, the suction operation is completed and the required amount of air layer 8 is filled. It is configured to be secured within a tank.

Of course, if the amount of ink in the main ink tank 12 is exhausted or small during this suction operation, ink will not be supplied or the amount supplied will be small.

Next, the configuration of the liquid amount detection and alarm device according to the present invention provided in the above configuration will be explained. Here, this device is referred to as an ink amount detection alarm device.

FIG. 2 shows the circuit configuration of the ink amount detection and alarm device. In the figure, a resistor indicated by the symbol RX is a resistor between the aforementioned electrode pair 9, and is connected to one end i of the resistor. This resistor R1, RX, this bridge circuit resistor R1
By detecting the potential difference between the connection point a between the resistors R2 and R3 with the comparator 17, it is possible to determine whether or not the ink level in the sub-ink tank 4 is above the electrode pair 9. is detected.

The output of this comparator 17 is passed through an AND gate 18 to the set input of a flip-flop 21, and is also passed through an inverter 19 and a Nant gate 20 to a set input of a clip-flop 21.
1 reset input. and gate 18
, the pulse of the detection timing signal P1 which is guided to the base of the transistor T1 via the current limiting resistor R4 at the time of detection is simultaneously introduced to the other input of each of the Nandt gates 20.

The flip-flop 21 is composed of, for example, a D flip-flop or a JK flip-flop, and is configured so that its output changes when the input changes from a low level to a no-no level. The AND gate 22 to which the input is connected is opened and closed.

The output of the AND gate 22 is connected to the base of the transistor T2 via a current limiting resistor R5, and the output of the AND gate 22 turns on and off the transistor T2. It's a moat, there is a power supply V+ on the collector side of transistor T2.
An alarm display LED 42' 3 is connected, and the emitter side is grounded. Current is applied to or cut off to the LED 23 by turning on or off the transistor T2, and the LED 23 is turned on or off.

On the other hand, an oscillator 27 that outputs pulses of an intermittent signal P2 is connected to the other input of the AND gate 22 via a Nandt gate 26. The output of the flip-flop 24 is connected to the other input of the Nant gate 26 via an inverter 25.

The flip-flop 24 is composed of a D or JK flip-flop like the flip-flop 21 described above, and its output changes as the input level changes from low to no. The set input is connected to the power supply via the inverter 28 and the resistor 7, and the input of the inverter 28 is grounded via the actuation switch 15a.
The voltage level applied to the set input of the flip-flop 24 is changed by turning on and off 5a. In addition, the reset input of the flip-flop 24 is connected to the reset input of the aforementioned 7-lip flop 21.
0 output is connected.

Next, the operation of the ink amount detection and warning device having the above configuration will be explained.

During non-detection, the pulse of the detection timing signal P1 is not guided to the transistor T1, and the transistor T1 is off, so the potential at the connection point a of the bridge circuit is higher than the potential at the connection point S, and the output of the comparator 17 is at the highest level.

Here, the AND gate 1B has a detection timing of P1/86. , Wow, that's big. A, F8. K), the set input of the 8-hung is at low level, and the flip-flop rough 21 separator lr1 is not set. In addition, it is inverted to low level by the high-level output cover inverter I9 of − and is guided to one input of the Nant gate 20. Since the other input of the Nant gate 20 is at low level, the output of the Nant gate 20 becomes high level. ing. Therefore, the flip-flop 21 is reset and the AND gate 22 is closed due to its low level output.

On the other hand, at this point, the operation of forcibly supplying ink to the sub-ink tank 4 is not performed, so the operation switch 15a is turned off, and the power supply voltage is inverted to a low level by the inverter 28 at the set input of the flip-flop 24. is applied.

Also, since the high level output from the Nant gate 20 is led to the reset input, the flip-flop 24 is reset, and the low level output is sent to the inverter 2.
5, it is inverted to high level and guided to the input of the Nant gate 26.

Therefore, the continuity signal P2, which is cut off from the oscillator 27 by the Nandt gate 26, is inverted by the Nantt gate 26 and guided to the AND gate 22. However, at this point, the AND gate 22 is closed as described above.

Since the output of the AND gate 22 is at a low level, the transistor T2 is turned off and the LED 23 is not turned on, so that no alarm is issued.

The ink amount is detected when the carriage 2 is stopped to avoid false detection, and a detection timing signal P1 is sent from a control circuit (not shown) to the circuit of the ink amount detection alarm device.

Here, if a sufficient amount of ink (2) exists in the sub-ink tank 4 and its liquid level is at a higher position than the electrode pair 9, the resistance RX between the electrode pair 9 will decrease to several hundred ohms due to the intervention of the ink I.
It is several MΩ.

A power supply voltage is applied to the electrode pair 9 in accordance with the pulse, and the comparator 17 detects the potential difference between the connection points a and b of the bridge circuit. The reason why voltage is not continuously applied to the electrode pair 9 here is to prevent electrolysis from occurring in the ink in the tank.

At this point, the resistance RX is several hundred liters (Ω to several MΩ), so the potential at the connection point a is lower than the potential at the connection points, and the output of the comparator 17 changes smoothly from high level to low level. .

Therefore, the output of the AND gate 18 is the detection timing signal P
Even if a 1 is brought to the input, it remains low level. On the other hand, the low level output of the converter 17 is inverted to a high level by the inverter 19 and guided to the Nant gate 20, so the output of the Nant gate 20 changes to low level and then returns to high level due to the input of the detection timing signal P1. .

Therefore, the flip-flop 21 continues to be in the reset state when no detection is detected, and the output remains at a low level, so the AND gate 22 is not opened. That is, due to the low level output of the AND gate 22, the transistor T2 is cut off, the LED 23 is not lit, and no alarm is issued.

Next, when the amount of ink in the sub-ink tank 4 decreases and the ink level becomes lower than the electrode pair 9, the resistance Rx becomes infinite due to the absence of ink between the electrode pair 9.

As a result, the potential at the connection point a becomes higher than the potential at the connection point S, so that the output of the comparator 17 changes from low level to high level. The high level output of the AND gate 18, which is a combination of this and the detection timing signal P1, sets the flip-flop 21, and the high level output opens the AND gate 22.

By opening the AND gate 22, the inverted intermittent signal P2 from the Nandt gate 26 side is transmitted to the transistor T.
2, and the transistor T2 is intermittently turned on. As a result, current is intermittently applied to the LED 23, the LBD 23 blinks intermittently, and an alarm is issued to the effect that the amount of ink in the sub-ink tank 4 is low.

Next, in response to this η information, the pump operation switch 1 is turned on to forcibly supply ink to the sub-ink tank 4.
When 5a is turned on automatically or manually, the set input of the flip-flop 24 is set to low level to high level, and the 7-lip 7a knob 24 is set.

As a result, the high level output of the shift flip-flop 24 is inverted to a low level by the inverter 25 and guided to the Nant gate 26, so that the output of the Nant gate 26 is fixed at a high level. That is, a continuous high level output is led to the base of the transistor T2, and the output of the transistor T
2 is continuously turned on, and the LED 23 is continuously lit.

Next, during this controlled ink supply, the main ink tank 1
When there is a sufficient amount of ink in the sub-ink tank 2 and the ink is supplied, the ink liquid level in the sub-ink tank 4 rises above the position of the electrode pair 9.

This lowers the resistance RX and the resistance value, making it compabe.

The output of the controller 1 goes from high level to low level again. The 7 lip 70 tube 21 is reset by the same operation as the detection when there is sufficient ink in the sub ink tank 4 described above, the AND gate 22 is closed, and the LED 23 is turned off. By turning off the light, the operator is informed that there is sufficient ink in the main ink tank and that ink has been supplied.

On the other hand, if the ink in the main ink tank 12 has run out, the resistance value of the resistor RX continues to be infinite, the output of the comparator 17 is up to the high level knob, the flip 70 knob 21 is in the set state, and the AND gate 22 is in the set state. Since the open state continues, the continuous lighting of the LED 23 continues.

This continuous lighting of the LED 23 allows the operator to know that the main ink tank 12 is out of ink. In other words, if the light remains on continuously even after the time required to complete the forced ink supply operation, this indicates that ink is not being supplied to the sub-ink tank 4, that is, the main This means that the ink in the ink tank 12 has run out. Since the time required to complete the above-mentioned supply operation is very short, the determination can be easily made.

According to the above configuration, a warning that the amount of ink in the sub-ink tank 4 is low is issued by the LED 23 blinking intermittently, and a warning that the main ink tank 12 is out of ink is issued by the LED 23 continuing for a predetermined time or longer. This is done by continuously lighting the lamp, and it is extremely easy to distinguish between the two. Moreover, by using one detection means (electrode pair) and one alarm means (LED), the amount of ink in the two tanks can be detected and an alarm can be issued based on the detection and output results.

In the present invention, the method of expressing the distinction between the LED alarms in the above embodiment is not limited to the above method, and may be, for example, the reverse of the above method. Further, it is also possible to configure the system so that a plurality of alarm means are used to separately issue alarms. Further, the alarm means is not limited to the optical means such as the LED in the embodiment, but other means such as an acoustic means such as a buzzer may be used, and the liquid amount detection means is not limited to the electrode pair.

Further, in the above embodiment, the ink supply operation may be automatically performed based on a detection output indicating that the amount of ink in the sub-ink tank 4 is small. Although the activation switch 15a is used as the activation switch for the pump 15, it may be a switch that is linked to the activation switch 15a.

Furthermore, the configuration of the present invention is not limited to the ink amount detection device for the inkjet recording device of the embodiment, but is also applicable to devices that consume liquid and have a plurality of tanks serving as storage tanks for the liquid and supplying the liquid from one to the other. The present invention can be applied to all liquid level detection and alarm devices that detect the liquid level in a tank and issue an alarm based on the detection result.

Effects As is clear from the above explanation, according to the present invention, in a liquid level detection/alarm device that detects the liquid level in a tank and outputs an alarm when the detected liquid level is below a predetermined level, Accordingly, means for detecting the operation of the means for supplying liquid to the tank is provided, and if the amount of liquid in the tank remains below the predetermined amount even after the operation of the supply means, a different alarm from the above is output. Therefore, detection of the liquid amount in a plurality of tanks, including the above-mentioned tank and a tank that supplies liquid to the same tank, and an alarm based on the detection result can be performed by a single detection means and an alarm means, respectively. Therefore, the number of parts is small and the space occupied is small, and the cost and size of devices such as inkjet recording devices in which this device is used can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a main part of an inkjet recording apparatus in which an ink amount detection and alarm device according to an embodiment of the present invention is used, and FIG. 2 is a circuit diagram showing the configuration of the ink amount detection and alarm device according to an embodiment. 1... Nozzle 4... Sub ink tank 9... Electrode pair 12... Main ink tank 15... Pump 15a... Operation switch 17... Comparator
18, 22... and Kate 19. 25, 28...
Inverter 20.26... Nantes Gate 21.24
...Flip-flop 27...Oscillator RX, R1-R7...Resistance TI
, T2...transistor

Claims (1)

[Scope of Claims] 1) In a liquid level detection/alarm device that detects the level of liquid in a tank and outputs an alarm when the detected level of liquid is below a predetermined level, the liquid is supplied to the tank in response to the alarm. A liquid quantity system characterized in that a means for detecting the operation of the supply means is provided, and if the liquid amount in the tank remains below the predetermined amount even after the operation of the supply means, a good news different from the warning is output. Detection alarm device. 2) The above-mentioned two types of alarms are combined into one alarm means. 3) The above-mentioned two types of alarms are configured to be expressed using different expression methods. The liquid level detection alarm device described.