Ink detection system

Abstract

The utility model relates to an ink detection system, comprising a photoelectric detection unit comprising a transmitting end and a receiving end which are oppositely arranged; the constant current module is electrically connected with the transmitting end of the photoelectric detection unit; and the main control module is electrically connected with the constant current module and the receiving end of the photoelectric detection unit. The device has the advantages that stable current is provided for the transmitting end of the photoelectric detection unit through the constant current module, so that the current of the transmitting end of the photoelectric detection unit is stabilized at a theoretical value, and the situation that forward current is abnormal due to the change of conduction voltage drop of a light-emitting diode can be effectively prevented; therefore, the detection result of the ink can be obtained by utilizing the relation between the light current of the receiving end of the photoelectric detection unit and the current of the transmitting end of the photoelectric detection unit, and the detection accuracy of the ink detection system is good.

Description

Technical Field

[0001] The utility model relates to the technical field of printers, in particular to an ink detection system. Background Art

[0002] An ink cartridge is provided in an inkjet printer. Usually, an ink level detection device is provided on the ink cartridge. When the ink level is insufficient, the user needs to be reminded to replace the ink cartridge.

[0003] To realize the detection of the ink in the ink cartridge, for example, a Chinese utility model patent with the patent number ZL202121204257.0 (the authorized publication number is CN216139692U) discloses a printing device. The ink level detection device therein includes a light source assembly, a photoelectric conversion device and a processor. The light source assembly irradiates light into the ink cartridge. The photoelectric conversion device is used to detect the light entering from the second chamber during the period when the light source assembly emits light. The processor detects the ink level in the ink cartridge according to the output of the photoelectric conversion device.

[0004] Although the above ink level detection device can realize the detection of ink through the photoelectric conversion device, the light source assembly in the prior art usually uses light-emitting diodes. Due to the difference in the forward voltage drop of the light-emitting diodes, the forward current of the light-emitting diodes is not stable in actual use, which will cause differences in the detection signals of the photoelectric conversion device and affect the accuracy of ink detection. Therefore, the prior art needs to be further improved. Summary of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide an ink detection system that can stabilize the current at the emission end of the photoelectric detection unit to ensure the detection accuracy at the receiving end in view of the above prior art.

[0006] The technical solution adopted by the utility model to solve the above technical problem is as follows: an ink detection system, comprising:

[0007] A photoelectric detection unit, including an emission end and a receiving end arranged oppositely;

[0008] It is characterized by further comprising:

[0009] A constant current module, electrically connected to the emission end of the photoelectric detection unit;

[0010] A main control module, electrically connected to the constant current module and the receiving end of the photoelectric detection unit.

[0011] Preferably, the constant current module includes a first switching device and a second switching device. The control end of the first switching device is connected to the first end of the second switching device and electrically connected to the main control module. The first end of the first switching device is electrically connected to the emitting end of the photoelectric detection unit. The second end of the first switching device is electrically connected to the control end of the second switching device and grounded through a fourth resistor. The second end of the second switching device is grounded.

[0012] Preferably, the control end of the first switching device is electrically connected to the main control module through a third resistor.

[0013] Preferably, the first switching device is a first triode. The control end of the first switching device is the base of the first triode. The first end of the first switching device is the collector of the first triode. The second end of the first switching device is the emitter of the first triode. Of course, the first switching device can also be a MOS tube or the like.

[0014] Preferably, the second switching device is a second triode. The control end of the second switching device is the base of the second triode. The first end of the second switching device is the collector of the second triode. The second end of the second switching device is the emitter of the second triode. Of course, the second switching device can also be a MOS tube or the like.

[0015] In the present utility model, the photoelectric detection unit is a photoelectric circuit breaker. The photoelectric circuit breaker includes a light emitting diode and a light receiver. The light emitting diode corresponds to the emitting end of the above-mentioned photoelectric detection unit, and the light receiver corresponds to the receiving end of the above-mentioned photoelectric detection unit.

[0016] Specifically, the anode of the light emitting diode is connected to the power supply through a first resistor, and the cathode of the light emitting diode is electrically connected to the constant current module.

[0017] Specifically, the first end of the light receiver is grounded. The second end of the light receiver is connected to the power supply through a second resistor. The second end of the light receiver corresponds to the signal output end of the light receiver. The signal output end of the light receiver is electrically connected to the main control module. The second end of the light receiver is also grounded through a first capacitor.

[0018] Preferably, the power supply is also grounded through a second capacitor.

[0019] Specifically, the light receiver is a photodiode or a phototransistor.

[0020] Compared with the prior art, the advantages of the present utility model are as follows: A constant current module provides a stable current for the transmitting end of the photoelectric detection unit, so that the current at the transmitting end of the photoelectric detection unit is stabilized at the theoretical value, thereby effectively preventing the abnormal forward current caused by the change in the conduction voltage drop of the light-emitting diode. Furthermore, the detection result of the ink can be obtained by utilizing the relationship between the photocurrent at the receiving end and the current at the transmitting end of the photoelectric detection unit, and the detection accuracy of this ink detection system is good. Brief Description of the Drawings

[0021] Figure 1 It is a specific circuit diagram of the ink detection system in the embodiment of the present utility model. Detailed Embodiment

[0022] The present utility model will be further described in detail below in conjunction with the embodiments of the drawings.

[0023] As Figure 1 shown, the ink detection system in this embodiment includes a photoelectric detection unit 1, a constant current module 2, and a main control module 3. The photoelectric detection unit 1 includes a transmitting end 11 and a receiving end 12 arranged opposite to each other; the constant current module 2 is electrically connected to the transmitting end 11 of the photoelectric detection unit 1; the main control module 3 is electrically connected to the constant current module 2 and the receiving end 12 of the photoelectric detection unit 1. The main control module 3 is configured to: be able to control the power supply of the constant current module 2 and be able to obtain the ink detection result according to the receiving end 12 of the photoelectric detection unit 1. This main control module 3 can be a controller commonly used in the prior art.

[0024] As Figure 1 shown, the photoelectric detection unit 1 in this embodiment is a photoelectric breaker. The photoelectric breaker includes a light-emitting diode U1 and a photoreceiver Q3. The light-emitting diode U1 corresponds to the transmitting end 11 of the above-mentioned photoelectric detection unit 1, and the photoreceiver Q3 corresponds to the receiving end 12 of the above-mentioned photoelectric detection unit 1. This light-emitting diode U1 is usually an infrared emitter that emits infrared light; the photoreceiver Q3 is a photodiode or a phototransistor.

[0025] The constant current module 2 includes a first switching device 21 and a second switching device 22. The control end of the first switching device 21 is connected to the first end of the second switching device 22 and is electrically connected to the main control module 3. The first end of the first switching device 21 is electrically connected to the transmitting end 11 of the photoelectric detection unit 1. The second end of the first switching device 21 is electrically connected to the control end of the second switching device 22 and is grounded through a fourth resistor R4. The second end of the second switching device 22 is grounded. In addition, the control end of the first switching device 21 is electrically connected to the main control module 3 through a third resistor R3.

[0026] As Figure 1As shown, the first switching device 21 in this embodiment is the first triode Q1. The control end of the first switching device 21 is the base of the first triode Q1. The first end of the first switching device 21 is the collector of the first triode Q1. The second end of the first switching device 21 is the emitter of the first triode Q1. Additionally, as Figure 1 shown, the second switching device 22 in this embodiment is the second triode Q2. The control end of the second switching device 22 is the base of the second triode Q2. The first end of the second switching device 22 is the collector of the second triode Q2. The second end of the second switching device 22 is the emitter of the second triode Q2.

[0027] The anode of the light-emitting diode U1 is connected to the power supply VCC through the first resistor R1. The cathode of the light-emitting diode U1 is electrically connected to the constant current module 2. The first end of the optical receiver Q3 is grounded. The second end of the optical receiver Q3 is connected to the power supply VCC through the second resistor R2. And the second end of the optical receiver Q3 corresponds to the signal output end of the optical receiver Q3. The signal output end of the optical receiver Q3 is electrically connected to the main control module 3. The second end of the optical receiver Q3 is also grounded through the first capacitor C1. Additionally, the power supply VCC is also grounded through the second capacitor C1.

[0028] Figure 1 The first resistor R1 in [] is 300Ω. The voltage of the power supply VCC is 3.3V. The voltage drop of the light-emitting diode U1 of the optoelectronic circuit breaker is VF = 1.2V. At this time, the forward current IF flowing through the light-emitting diode is 7mA. However, since VF is not fixed at 1.2V, that is, the forward current of the light-emitting diode cannot be stabilized at 7mA. According to the linear relationship between the photocurrent on the light-receiving side (the current of the optical receiver Q3) and the forward current on the light-emitting side (the forward current of the light-emitting diode) of the optoelectronic circuit breaker, it is theoretically calculated that the optoelectronic circuit breaker within the fixed specification range cannot work properly.

[0029] The working process of the ink detection system in this embodiment is as follows:

[0030] Figure 1The third resistor R3 therein is 5 KΩ, the fourth resistor R4 is 100 Ω, the main control module 3 outputs a working current of 3.3 V, the base and emitter of the first triode Q1 start to conduct, the first triode Q1 operates in the amplification state, the current output by the first triode Q1 gradually increases, and the voltage drop across the fourth resistor R4 gradually rises at the same time, that is: the base voltage of the second triode Q2 starts to rise; when the voltage of the base of the second triode Q2 is greater than 0.5 V, the base and emitter of the second triode Q2 start to conduct, and the second triode Q2 operates in the amplification state; when the base voltage of the second triode Q2 is greater than 0.7 V, the second triode Q2 enters the saturation state. At this time, the base voltage of the first triode Q1 is pulled by the second triode Q2 to be close to the voltage of the ground terminal GND, resulting in the first triode Q1 being unable to work, and the first triode Q1 enters the cut-off state;

[0031] It shows that the first triode Q1 and the second triode Q2 restrict each other, and there is no situation where one works in the saturation region. Under the action of the Vbe clamping of the two triodes, this constant current module can work normally; since the voltage drop of Vbe is usually 0.7 V in the critical amplification state of the triode, that is, the voltage drop of the resistor R4 is 0.7 V, the constant current Ie1 flowing through the emitter of the first triode Q1 can be calculated as Ie1 = 0.7 V / 100 Ω = 7 mA, that is, the forward current of the light-emitting diode can be stabilized at 7 mA, meeting the requirements of the theoretical working design.

[0032] When keeping the forward current of the light-emitting side of the optoelectronic circuit breaker constant, the infrared light emission intensity can be made constant, that is: the photocurrent of the light-receiving side is constant and has a linear relationship with the forward current of the light-emitting side. By calculating the forward current calculation ratio specified in the factory test of the manufacturer, the photocurrent of the light-receiving side can be obtained by proportional scaling according to the specifications of the optoelectronic circuit breaker itself; the photocurrent magnitude of the optoelectronic circuit breaker within a fixed specification range affects the electrical signal output. When there is no occlusion in the optical path between the transmitting end 11 and the receiving end 12, the photocurrent of the light-receiving side is large, the signal output terminal of the photoreceiver Q3 outputs a low level and the ink volume is below the judgment standard, indicating that the ink is insufficient; when there is ink occluding the optical path, the photocurrent of the light-receiving side suddenly decreases, the signal output terminal of the photoreceiver Q3 outputs a high level and the ink volume is above the judgment standard, indicating that the ink is sufficient.

[0033] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An ink detection system, comprising: A photoelectric detection unit (1), including a transmitting end (11) and a receiving end (12) arranged oppositely; It is characterized by further comprising: A constant current module (2), electrically connected to the transmitting end (11) of the photoelectric detection unit (1); A main control module (3), electrically connected to the constant current module (2) and the receiving end (12) of the photoelectric detection unit (1).

2. The ink detection system according to claim 1, wherein: The constant current module (2) includes a first switching device (21) and a second switching device (22). The control end of the first switching device (21) is connected to the first end of the second switching device (22) and is electrically connected to the main control module (3). The first end of the first switching device (21) is electrically connected to the transmitting end (11) of the photoelectric detection unit (1). The second end of the first switching device (21) is electrically connected to the control end of the second switching device (22) and is grounded through a fourth resistor (R4). The second end of the second switching device (22) is grounded.

3. The ink detection system according to claim 2, wherein: The control end of the first switching device (21) is electrically connected to the main control module (3) through a third resistor (R3).

4. The ink detection system according to claim 2, wherein: The first switching device (21) is a first triode (Q1). The control end of the first switching device (21) is the base of the first triode (Q1). The first end of the first switching device (21) is the collector of the first triode (Q1). The second end of the first switching device (21) is the emitter of the first triode (Q1).

5. The ink detection system according to claim 2, wherein: The second switching device (22) is a second triode (Q2). The control end of the second switching device (22) is the base of the second triode (Q2). The first end of the second switching device (22) is the collector of the second triode (Q2). The second end of the second switching device (22) is the emitter of the second triode (Q2).

6. The ink detection system according to any one of claims 1 to 5, characterized in that: The photoelectric detection unit (1) is a photoelectric circuit breaker. The photoelectric circuit breaker includes a light-emitting diode (U1) and a photoreceiver (Q3). The light-emitting diode (U1) corresponds to the transmitting end (11) of the above-mentioned photoelectric detection unit (1). The photoreceiver (Q3) corresponds to the receiving end (12) of the above-mentioned photoelectric detection unit (1).

7. The ink detection system according to claim 6, wherein: The anode of the light-emitting diode (U1) is connected to a power supply (VCC) through a first resistor (R1). The cathode of the light-emitting diode (U1) is electrically connected to the constant current module (2).

8. The ink detection system according to claim 7, wherein: The first end of the photoreceiver (Q3) is grounded. The second end of the photoreceiver (Q3) is connected to the power supply (VCC) through a second resistor (R2). And the second end of the photoreceiver (Q3) corresponds to the signal output end of the photoreceiver (Q3). The signal output end of the photoreceiver (Q3) is electrically connected to the main control module (3). The second end of the photoreceiver (Q3) is also grounded through a first capacitor (C1).

9. The ink detection system according to claim 8, wherein: The power supply (VCC) is also grounded through a second capacitor (C2).

10. The ink detection system according to claim 8, wherein: The photoreceiver (Q3) is a photodiode or a phototransistor.

Images