Reading circuit, control board and ink-jet printing equipment

Abstract

The utility model discloses a reading circuit, a control board and an ink-jet printing device, and relates to the technical field of printing, the reading circuit is applied to the ink-jet printing device, the ink-jet printing device comprises a nozzle, the reading circuit comprises a nozzle connecting end, a first signal end, a second signal end and a voltage conversion circuit, the nozzle connecting end is used for connecting the nozzle, and the first signal end is used for connecting the nozzle. The first signal end is connected with the main control circuit and the nozzle connecting end and used for outputting a reading signal output by the main control circuit to the nozzle through the nozzle connecting end so that the nozzle can output an identification signal through the nozzle connecting end, the second signal end is used for being connected into the main control circuit, and the voltage conversion circuit is arranged between the nozzle connecting end and the second signal end in series; the voltage of the identification signal output by the nozzle connecting end is adjusted to a first preset voltage and then is output to the second signal end. The utility model aims to improve the problem that the level feedback of the nozzle is not matched with the master control circuit, improve the printing quality and efficiency, and further improve the user experience.

Description

Technical Field

[0001] This application relates to the field of printing technology, and in particular to a reading circuit, a control board, and an inkjet printing device. Background Technology

[0002] In inkjet printers, the main control circuit needs to identify the ID information output by the printhead to ensure that the printer can communicate correctly with the installed printhead and adjust printing parameters such as droplet size, jet frequency, and heating temperature according to the specific model and characteristics of the printhead. These parameters directly affect print quality and efficiency.

[0003] When the main control circuit encounters a voltage mismatch issue when reading the printhead ID (for example, the printhead feedback voltage is only 1.5V, while the main control circuit requires 3.3V for correct identification), the following problems may occur: The main control circuit cannot correctly read the printhead ID, thus failing to determine the printhead type and characteristics, causing the printer to be unable to load the correct configuration file, thereby affecting print quality. Because it cannot correctly identify the printhead, the main control circuit may default to loading a generic or inappropriate configuration file, which may lead to poor print quality, color deviation, and other problems. Furthermore, if the printhead is incompatible with the printer, prolonged use may damage the printhead or other components. Utility Model Content

[0004] The main purpose of this invention is to provide a reading circuit, control board, and inkjet printing device, which aims to improve the mismatch between printhead level feedback and main control circuit, improve printing quality and efficiency, and thus enhance user experience.

[0005] To achieve the above objectives, this utility model proposes a reading circuit for use in an inkjet printing device, the inkjet printing device including a printhead and a main control circuit, the reading circuit including:

[0006] The nozzle connection terminal is used to connect to the nozzle, send a read signal to the nozzle, and receive the identification signal output by the nozzle;

[0007] The first signal terminal is connected to the nozzle connection terminal and is used to receive the read signal output by the main control circuit and output it to the nozzle connection terminal.

[0008] The second signal terminal is used to connect to the main control circuit and output the identification signal;

[0009] A voltage conversion circuit is connected in series between the nozzle connection terminal and the second signal terminal;

[0010] The voltage conversion circuit is used to convert the voltage of the identification signal output from the nozzle connection terminal into a first preset voltage and then output it to the second signal terminal.

[0011] In one embodiment, the reading circuit further includes: a power input terminal for providing the first preset voltage; the voltage conversion circuit includes:

[0012] The NOT gate circuit has its first terminal electrically connected to the nozzle connection terminal, and its second terminal electrically connected to the second signal terminal and the power input terminal, respectively.

[0013] The NOT gate is used to disconnect when the identification signal is received, so as to output the first preset voltage to the second signal terminal.

[0014] In one embodiment, the NOT gate circuit includes:

[0015] A first resistor, the first end of which is electrically connected to the power input terminal;

[0016] A switching transistor, the first end of which is connected to the nozzle connection terminal, the second end of which is electrically connected to the second signal terminal and the second end of the first resistor, and the third end of which is grounded;

[0017] The switching transistor is configured to: disconnect the electrical connection between the nozzle connection terminal and the second signal terminal when receiving an identification signal from the nozzle connection terminal, so as to output a first preset voltage to the second signal terminal; and, when not receiving an identification signal from the nozzle connection terminal, connect the electrical connection between the nozzle connection terminal and the second signal terminal, so as to output a second preset voltage to the second signal terminal.

[0018] In one embodiment, the switching transistor includes a bipolar transistor, the base of which is electrically connected to the nozzle connection terminal, the collector of which is electrically connected to the second signal terminal and the second terminal of the first resistor, and the emitter of which is grounded.

[0019] In one embodiment, the read circuit further includes:

[0020] A pull-up circuit is provided, wherein the first end of the pull-up circuit is electrically connected to the power input terminal; and the second end of the pull-up circuit is electrically connected to both the nozzle connection terminal and the voltage conversion circuit.

[0021] The pull-up circuit is used to pull up the voltage of the nozzle connection terminal to a first preset voltage when the identification signal is not connected to the nozzle connection terminal. The NOT gate circuit is used to conduct under the first preset voltage so that the output voltage of the second signal terminal is the second preset voltage.

[0022] In one embodiment, the read circuit further includes:

[0023] A current limiting circuit, wherein the first terminal of the current limiting circuit is electrically connected to the power input terminal and the nozzle connection terminal, and the second terminal of the current limiting circuit is electrically connected to the first terminal of the voltage conversion circuit;

[0024] The current limiting circuit is used to limit the current flowing to the first terminal of the voltage conversion circuit within a preset current range.

[0025] In one embodiment, the read circuit further includes:

[0026] An impedance matching circuit is provided, wherein the first end of the impedance matching circuit is electrically connected between the nozzle connection terminal and the voltage conversion circuit, and the second end of the impedance matching circuit is electrically connected to the first signal terminal.

[0027] This utility model proposes a control board, the control board comprising:

[0028] The reading circuit described in any one of the above; and

[0029] The main control circuit has a first interface and a second interface. The first interface is connected to the first signal terminal of the reading circuit, and the second interface is connected to the second signal terminal of the reading circuit. The main control circuit is used to output a reading signal to the reading circuit through the first interface and to receive the identification signal through the second interface.

[0030] In one embodiment, the first interface is an input / output interface, the first interface has an input mode and an output mode, the first interface is used to output a read signal to the first signal terminal in the output mode, and to switch to the input mode after outputting the read signal.

[0031] This utility model also proposes an inkjet printing device, which includes a printhead and a reading circuit as described in any one of the above-mentioned embodiments, wherein the printhead connection terminal of the reading circuit is electrically connected to the printhead; or,

[0032] The inkjet printing device includes a printhead and the control board described above, wherein the printhead is electrically connected to the control board.

[0033] This invention proposes a reading circuit for use in an inkjet printing device. The inkjet printing device includes a printhead and a main control circuit. The reading circuit includes a printhead connection terminal, a first signal terminal, a second signal terminal, and a voltage conversion circuit. The printhead connection terminal is used to connect to the printhead, send a reading signal to the printhead, and receive an identification signal output by the printhead. The first signal terminal is connected to the printhead connection terminal and is used to receive the reading signal output by the main control circuit and output it to the printhead connection terminal. The second signal terminal is used to connect to the main control circuit and output the identification signal. The voltage conversion circuit is connected in series between the printhead connection terminal and the second signal terminal; it is used to convert the voltage of the identification signal output by the printhead connection terminal into a first preset voltage and then output it to the second signal terminal.

[0034] In practical applications, when the voltage of the printhead output identification signal is too low (e.g., 1.5V) and cannot be correctly recognized by the main control circuit, this invention uses a voltage conversion circuit to convert the voltage of the identification signal and output it to the second signal terminal. This can adjust the voltage of the identification signal to a first preset voltage (e.g., 3.3V). The main control circuit detects the voltage amplitude of the converted identification signal and can then correctly identify it, thereby determining the printhead information and entering the normal printing process. This improves the problem of printhead level feedback mismatch, enhances printing quality and efficiency, and ultimately improves the user experience. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a module of an embodiment of the reading circuit of this utility model;

[0037] Figure 2 This is a schematic diagram of another embodiment of the reading circuit of this utility model;

[0038] Figure 3 This is a schematic diagram of another embodiment of the reading circuit of this utility model;

[0039] Figure 4 This is a schematic diagram of another embodiment of the reading circuit of this utility model;

[0040] Figure 5 This is a schematic diagram of another embodiment of the reading circuit of this utility model;

[0041] Figure 6This is a detailed circuit diagram of one embodiment of the reading circuit of this utility model;

[0042] Figure 7 This is a schematic diagram of another embodiment of the reading circuit of this utility model;

[0043] Figure 8 This is a schematic diagram of another embodiment of the reading circuit of this utility model;

[0044] Figure 9 This is a schematic diagram of another embodiment of the reading circuit of this utility model.

[0045] Explanation of icon numbers:

[0046] 10. Printhead connection terminal; 20. Second signal terminal; 30. Voltage conversion circuit; 40. Power input terminal; 50. Pull-up circuit; 60. Current limiting circuit; 70. Impedance matching circuit; 31. NOT gate circuit; 32. Switching transistor; 33. First resistor; 100. Main control circuit; 110. First signal terminal; 120. Filtering circuit; 130. Signal isolation circuit; 1. Printhead; 2. Reading circuit; 3. Control board; 4. Inkjet printing equipment.

[0047] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0048] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0049] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0050] In inkjet printers, the main control circuit needs to identify the printhead's output ID information to ensure the printer can correctly communicate with the installed printhead and adjust printing parameters such as droplet size, ejection frequency, and heating temperature according to the printhead's specific model and characteristics. These parameters directly affect print quality and efficiency. When the main control circuit encounters a voltage mismatch problem when reading the printhead ID (for example, the printhead feedback voltage is only 1.5V, while the main control circuit requires 3.3V for correct identification), the following problems may occur: the main control circuit cannot correctly read the printhead ID, thus failing to determine the printhead's type and characteristics. This will cause the printer to fail to load the correct configuration file, thereby affecting print quality. Due to the inability to correctly identify the printhead, the main control circuit may default to loading a generic or inappropriate configuration file, which may lead to poor print quality, color deviation, and other problems. Furthermore, if the printhead is incompatible with the printer, prolonged use may damage the printhead or other components.

[0051] It should be noted that the main control circuit is typically designed to recognize digital signals within a certain voltage range. For example, for a system with a supply voltage of 3.3V, the main control circuit might be configured to recognize voltages above a certain threshold (e.g., 2V) as logic "1" and voltages below another threshold (e.g., 0.8V) as logic "0" to ensure signal reliability and interference immunity. If the voltage fed back from the nozzle is only 1.5V, it is clearly within the uncertainty region of the main control circuit. This voltage falls neither within the range of logic "1" nor logic "0," and the main control circuit cannot correctly recognize the voltage signal fed back from the nozzle as a valid digital signal. Therefore, in order for the main control circuit to correctly recognize the ID signal fed back from the nozzle, a method is needed to adjust the voltage to a range that the main control circuit can recognize.

[0052] Therefore, refer to Figure 1This invention proposes a reading circuit 2 for use in an inkjet printing device. The inkjet printing device includes a printhead 1 and a control board 3. The control board 3 is equipped with a main control circuit 100 and the reading circuit 2. The printhead 1 is used to spray ink onto a printing medium (such as paper) to form text or images, and also has the function of outputting identification information to identify the printhead 1's model, characteristics, and other identification information. For example, after receiving a reading signal output by the main control circuit 100, the printhead 1 outputs a corresponding identification signal to the reading circuit 2 through a specific pin (such as HEAD_ID), so that the main control circuit 100 can identify the printhead 1's model, characteristics, and other relevant identification information. It is understood that the reading circuit 2 and the main control circuit 100 are located on the same control board 3 and communicate through specific pins and signal lines. The main control circuit 100 receives the identification signal output by the printhead 1 via the reading circuit 2 and analyzes the received signal to adjust the printing parameters according to the printhead 1's model and characteristics, ensuring the smooth execution of the printing task, and thus ensuring the high efficiency and reliability of the inkjet printing device.

[0053] In some embodiments, the read circuit 2 includes:

[0054] The nozzle connection terminal 10 is used to connect to the nozzle 1, send a read signal to the nozzle 1, and receive the identification signal output by the nozzle 1.

[0055] The first signal terminal 110 is connected to the nozzle connection terminal 10 and is used to receive the read signal output by the main control circuit 100 and output it to the nozzle connection terminal 10.

[0056] The second signal terminal 20 is used to connect to the main control circuit 100 and output an identification signal;

[0057] A voltage conversion circuit 30 is connected in series between the nozzle connection terminal 10 and the second signal terminal 20.

[0058] The voltage conversion circuit 30 is used to convert the voltage of the identification signal output from the nozzle connection terminal 10 into a first preset voltage and then output it to the second signal terminal 20.

[0059] In this embodiment, the voltage conversion circuit 30 can be implemented using NOT gate circuits, such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), transistors, and other switching devices and peripheral circuits, or it can be implemented using a voltage conversion chip. Alternatively, the voltage conversion circuit 30 can also be implemented using voltage conversion chips, level conversion chips, etc., which will not be listed here.

[0060] Specifically, the first interface of the main control circuit 100 is electrically connected to the reading circuit 2 via the first signal terminal 110. The first interface has an input mode and an output mode. During the initialization phase, the main control circuit 100 sets the first interface to output mode and sends a reading signal to the first signal terminal 110 via the first interface, so that the printhead 1 receives the reading signal output by the main control circuit 100 via the printhead connection terminal 10. After sending the reading signal, the main control circuit 100 can switch the first interface to input mode. It should be noted that the printhead connection terminal 10 can also have input and output modes. When the printhead 1 receives the reading signal via the printhead connection terminal 10, it outputs the corresponding identification signal to the printhead connection terminal 10. When the identification signal is connected to the printhead connection terminal 10, the voltage conversion circuit 30 converts the voltage of the identification signal to a first preset voltage and outputs it to the second signal terminal 20, so that the main control circuit 100 receives the identification signal via the second interface, accurately identifies the identification signal output by the printhead 1, and adjusts the printing parameters according to the specific model and characteristics of the printhead 1 to ensure the normal operation of the inkjet printing equipment. It should be noted that the first preset voltage can be set in advance according to actual needs.

[0061] In practical applications, when the voltage output by printhead 1 is low (e.g., 1.5V), and cannot be correctly recognized by the main control circuit 100 after being output through printhead connection terminal 10 and second signal terminal 20, this invention employs a voltage conversion circuit 30 to convert the voltage of the identification signal before outputting it to the second signal terminal 20. This can adjust the voltage of the identification signal to a first preset voltage (e.g., 3.3V). The main control circuit 100 detects the voltage amplitude of the converted identification signal through its second interface, thereby determining the identification signal of printhead 1, identifying the identity information of printhead 1, and entering the normal printing process. This improves the problem of mismatched printhead 1 level feedback, enhances printing quality and efficiency, and ultimately improves the user experience.

[0062] In one embodiment, the reading circuit 2 further includes a power input terminal 40 for providing a first preset voltage; the voltage conversion circuit 30 includes a NOT gate circuit 31, the first terminal of which is electrically connected to the nozzle connection terminal 10, and the second terminal of which is electrically connected to the second signal terminal 20 and the power input terminal 40 respectively; the NOT gate circuit 31 is used to disconnect when receiving the identification signal connected to the nozzle connection terminal 10, so as to output the first preset voltage to the second signal terminal 20.

[0063] In some embodiments, the NOT gate circuit 31 can be implemented using transistors, MOSFETs, comparators, etc.

[0064] The following is a detailed explanation using a transistor-based NOT gate circuit 31 as an example. (Refer to...) Figure 2The power input terminal 40 can be connected to a power source to provide power to the nozzle 1 and the main control circuit 100. The first preset voltage connected to the power input terminal 40 serves as the reference for the operation of the entire circuit. The NOT gate circuit 31 requires a stable power supply to ensure that the output signal can reach the expected logic level. In digital circuits, the definition of high and low levels is based on the power supply voltage. For example, in a 3.3V system, voltages higher than 2.0V are usually considered logic high, and voltages lower than 0.8V are considered logic low. The first preset voltage (e.g., 3.3V) provided by the power input terminal 40 serves as the reference for the high level, ensuring that the output signal can reach or approach this voltage value when the logic level is high. When the nozzle connection terminal 10 is not connected to the identification signal, the transistor is turned on, and the output level signal is pulled low. When the nozzle connection terminal 10 is connected to the identification signal, the transistor is turned off, and the output level signal is pulled high to 3.3V to output the first preset voltage to the second signal terminal 20, so that the main control circuit 100 can receive the identification signal through the second interface and obtain the identification information of the nozzle 1. Without a stable 3.3V voltage provided by the power input terminal 40, the output terminal may not be able to reach the required high level, causing the main control chip to be unable to correctly recognize the signal.

[0065] Specifically, when the nozzle connection terminal 10 receives the identification signal output from nozzle 1, the NOT gate circuit 31 outputs a high-level signal. For example, the voltage of the identification signal output from the second signal terminal 20 is pulled up to 3.3V. After receiving the identification signal, the main control circuit 100 inverts the level of the identification signal, which is the ID of nozzle 1. At this time, the presence of the power input terminal 40 ensures that the circuit can work normally in other states. When the signal input terminal does not receive the identification signal from nozzle 1, the first terminal of the NOT gate circuit 31 receives a high-level signal, which pulls the voltage of the identification signal low. At this time, the main control circuit 100 receives a low-level signal and inverts it. In addition, the power input terminal 40 can also provide the necessary operating voltage for each component in the reading circuit 2, thereby improving the reliability and stability of the reading circuit 2.

[0066] The first preset voltage provided by the power input terminal 40 serves as a reference voltage, ensuring that the signal output by the NOT gate 31 can reach the digital signal that the main control circuit 100 can recognize. When the 1.5V signal output from the printhead 1 is connected, the NOT gate 31 converts this level to a recognizable logic low level (0V), enabling the main control circuit 100 to accurately recognize the information from the printhead 1, thereby improving printing quality and efficiency. Furthermore, the power input terminal 40 not only provides a reference for the high-level output but also ensures the normal operation of the entire circuit, guaranteeing the accuracy and reliability of signal conversion.

[0067] In one embodiment, reference Figure 3 The NOT gate circuit 31 includes:

[0068] The first resistor 33, the first end of the first resistor 33 is electrically connected to the power input terminal 40;

[0069] The first end of the switch tube 32 is connected to the nozzle connection terminal 10, the second end of the switch tube 32 is electrically connected to the second signal terminal 20 and the second end of the first resistor 33, and the third end of the switch tube is grounded.

[0070] The switching transistor 32 is configured to: disconnect the electrical connection between the nozzle connection terminal 10 and the second signal terminal 20 when an identification signal is received from the nozzle connection terminal 10, so as to output a first preset voltage to the second signal terminal 20; and, when no identification signal is received from the nozzle connection terminal 10, connect the electrical connection between the nozzle connection terminal 10 and the second signal terminal 20, so as to output a second preset voltage to the second signal terminal 20.

[0071] In this embodiment, the switching transistor 32 can be implemented using a transistor, MOSFET, or the like, and the resistance value of the first resistor 33 can be set in advance by the R&D personnel.

[0072] Optionally, the switching transistor 32 includes a transistor, the base of which is electrically connected to the nozzle connection terminal 10, the collector of which is electrically connected to the second signal terminal 20 and the second terminal of the first resistor 33, and the emitter of which is grounded.

[0073] refer to Figure 6 Q1 is a transistor, the communication pin of HEAD-ID nozzle 1, connected to nozzle connection terminal 10. VCC is the power input terminal 40. IO1 is the first interface of the main control circuit 100, connected to the first signal terminal 110. IO2 is the second interface of the main control circuit 100, connected to the second signal terminal 20. The base b of transistor Q1 is electrically connected to nozzle connection terminal 10. The collector of transistor Q1 is electrically connected to power input terminal 40 through the first resistor 33. The emitter of transistor Q1 is grounded. It should be noted that IO1 is a bidirectional signal input / output pin, with input and output modes. In output mode, IO1 outputs a read signal to the first signal terminal 110. Upon receiving the read signal, the nozzle 1 transmits its identification signal to the nozzle connection terminal 10. Because the voltage amplitude of the identification signal is relatively low, the main control circuit 100 cannot correctly identify the ID of the nozzle 1 via the first signal terminal 110. At this time, the transistor Q1 performs level conversion, converting the voltage of the identification signal to a first preset voltage. The second interface of the main control circuit 100 receives the signal output from the second signal terminal 20 to ensure that the signal level is sufficiently high (reaching a preset voltage VCC, such as 3.3V). Therefore, the main control circuit 100 can correctly identify the signal from IO2 and obtain the ID information of the nozzle 1. In this embodiment, the first preset voltage is greater than the second preset voltage.

[0074] Specifically, Q1 acts as a switch 32. When its base (b) receives sufficient drive current, the collector (c) and emitter (e) will conduct, forming a path for current to flow. In this embodiment, when the nozzle 1 sends an identification signal, the base of Q1 will not receive enough current to turn it on, and Q1 will be in the off state. Therefore, the collector voltage of Q1 is close to VCC (3.3V), which is equivalent to a logic high level. At this time, the main control circuit 100 identifies the high-level signal through IO2, and after inversion, it becomes the level of the identification signal of the nozzle 1. Conversely, when the nozzle 1 does not send an identification signal, Q1 is turned on, and the collector voltage is pulled low, close to 0V, which is equivalent to a logic low level. The main control circuit 100 identifies the low-level signal through IO2, and after inversion, it determines that the nozzle 1 has not output an identification signal. Therefore, after the identification signal from nozzle 1 is converted by Q1, the originally low voltage (e.g., the voltage fed back by nozzle 1 is 1.5V) is converted into a high-level signal close to VCC (3.3V). This allows the main control circuit 100 to correctly identify the identification signal sent by nozzle 1 via the second signal terminal 20. To obtain the true ID signal of nozzle 1, the main control circuit 100 only needs to invert the level on IO2 to recover the data corresponding to the original identification signal sent by nozzle 1.

[0075] Transistor Q1 acts as a level converter and signal amplifier, increasing the originally low voltage of the marking signal output from printhead 1 to a voltage range that the main control chip can recognize. This improves the level feedback mismatch problem of printhead 1, enhances printing quality and efficiency, and ultimately improves the user experience. Meanwhile, the use of resistors and NPN transistors to form a NOT gate circuit 31 reduces the design cost of the reading circuit 2.

[0076] It should be noted that in digital circuits, if an input pin is not connected to any signal source (i.e., floating), its voltage level is unpredictable. This can cause the input pin to fluctuate randomly due to noise or static electricity.

[0077] In other embodiments, a MOSFET can be used instead of transistor Q1, which will not be elaborated here. Alternatively, multiple transistors or MOSFETs can be used.

[0078] In one embodiment, reference Figure 4 The reading circuit 2 also includes:

[0079] Pull-up circuit 50, the first end of pull-up circuit 50 is electrically connected to power input terminal 40; the second end of pull-up circuit 50 is electrically connected to nozzle connection terminal 10 and voltage conversion circuit 30 respectively.

[0080] The pull-up circuit 50 is used to pull up the voltage of the nozzle connection terminal 10 to a first preset voltage when the identification signal is not connected to the nozzle connection terminal 10. The NOT gate circuit is used to conduct under the first preset voltage so that the output voltage of the second signal terminal 20 is the second preset voltage.

[0081] In some embodiments, the pull-up circuit 50 can be implemented using a pull-up resistor R1, a diode pull-up circuit, a transistor pull-up circuit, etc. (See reference) Figure 6 The first end of resistor R1 is electrically connected to the 40VCC power input terminal, and the second end of R1 is electrically connected to the nozzle connection terminal 10. When nozzle 1 does not send an identification signal, the pull-up resistor R1 pulls the HEAD_ID pin (equivalent to nozzle connection terminal 10) up to VCC (e.g., 3.3V). At this time, the NOT gate (transistor) is turned on, and the second signal terminal 20 outputs a second preset voltage. This ensures that nozzle connection terminal 10 is in a defined high-level state when there is no identification signal, thus avoiding the floating problem. This provides a default logic state for nozzle connection terminal 10. When nozzle 1 does not send any signal, the HEAD_ID pin remains high as a default logic state, which can be recognized by the main control circuit 100 and used to initialize or configure related hardware resources. When the printhead connection terminal 10 is connected to the identification signal, the HEAD_ID pin is in a low logic state, the transistor Q1 is cut off, and the voltage is pulled high to 3.3V. The main control circuit 100 recognizes the high-level signal through IO2. In this way, the main control circuit 100 can identify the ID of printhead 1 through the level state to complete the printing work.

[0082] It should be noted that if the HEAD_ID pin is in a low or uncertain state when no identification signal is received, it may cause false triggering. For example, if the HEAD_ID pin goes low due to noise, the main control circuit 100 may mistakenly interpret it as the printhead 1 sending a signal. This application uses a pull-up resistor to set the HEAD_ID pin to a high level by default, which can reduce the possibility of such false triggering and improve the reliability and stability of printing operations.

[0083] R1 acts as a pull-up resistor, ensuring that the nozzle connection terminal 10 remains at a high level when there is no external signal, preventing the signal from floating and reducing false triggering. It also works in conjunction with transistor Q1 to ensure that the reading circuit 2 can correctly perform level conversion and signal processing, thereby allowing the main control circuit 100 to accurately identify the information from the nozzle 1. This improves the stability and reliability of the reading circuit 2.

[0084] To improve the reliability and stability of the read circuit 2, in one embodiment, reference is made to... Figure 5 The reading circuit 2 also includes:

[0085] The current limiting circuit 60 has its first terminal electrically connected to the power input terminal 40 and the nozzle connection terminal 10, and its second terminal electrically connected to the first terminal of the voltage conversion circuit 30.

[0086] The current limiting circuit 60 is used to limit the current flowing to the first terminal of the voltage conversion circuit 30 within a preset current range.

[0087] In this embodiment, the current limiting circuit 60 can be implemented using a current limiting resistor, a constant current source, a current mirror, a linear regulator, etc. This embodiment will use a current limiting resistor as an example for explanation.

[0088] refer to Figure 6 R2 is a current-limiting resistor. The first end of R2 is electrically connected to the common terminal of the power input terminal 40 and the nozzle connection terminal 10, and the second end of R2 is electrically connected to the base of transistor Q1. Additionally, R3 is a small resistor or a 0Ω resistor; the first resistor R4 and Q1 form a NOT gate circuit 31. Since the base-emitter junction of the transistor is a PN junction, it has a certain maximum allowable current (Ib_max). If the base current is too large, exceeding this maximum allowable current, it may cause the PN junction to overheat or even burn out. This application uses R2 as a current-limiting resistor to ensure that the base current is kept within a preset current range, thereby protecting the transistor from damage. The resistance value of R2 is set in advance by the researchers to ensure that the base current is within a safe range. It is understandable that if the base current is not limited, changes in the signal at the nozzle connection terminal 10 may cause significant fluctuations in the collector current, affecting the stability of the circuit.

[0089] R2 acts as a current-limiting resistor, effectively protecting transistor Q1. When designing read circuit 2, a suitable value for R2 is chosen to ensure the base current remains within a safe range. This improves the reliability and stability of read circuit 2.

[0090] In another embodiment, reference Figure 7 The reading circuit 2 also includes:

[0091] The filter circuit 120 has its input terminal electrically connected to the nozzle connection terminal 10, and its output terminal electrically connected to the voltage conversion circuit 30.

[0092] The filter circuit 120 is used to filter the identification signal and output it to the voltage conversion circuit 30.

[0093] In this embodiment, the filter circuit 120 can be implemented using one or more combinations of capacitors, resistors, and inductors, such as RC filters, LC filters, etc.

[0094] It should be noted that the identification signal may contain various types of interference signals, which can adversely affect the integrity and reliability of the signal. For example, electromagnetic radiation generated by motors, switching power supplies, and wireless equipment may interfere with the identification signal, causing signal distortion and preventing the main control circuit 100 from correctly identifying the logic level of the signal, thus preventing normal operation. Therefore, in this embodiment, after receiving the read signal output by the main control circuit 100, the printhead 1 outputs the corresponding identification signal to the printhead connection terminal 10. The filtering circuit 120 (such as an RC filter) filters the identification signal and outputs it to the voltage conversion circuit 30, so that the voltage conversion circuit 30 adjusts the voltage of the filtered identification signal to a first preset voltage and outputs it to the second signal terminal 20. For example, it converts the 1.5V of the printhead 1 feedback information (identification signal) to 3.3V, so that the main control circuit 100 can accurately identify the ID information of the printhead 1 and adjust the parameters for printing. By selecting appropriate Rf and Cf values, the cutoff frequency of the filter is made lower than the frequency of the identification signal to ensure signal integrity.

[0095] By adding a filter circuit 120, noise in the identification signal output by printhead 1 can be effectively filtered out, improving signal stability and reliability. The filter circuit 120 works in conjunction with the voltage conversion circuit 30 to ensure that the main control circuit 100 can accurately identify the ID information of printhead 1, thereby improving the performance of the inkjet printing equipment and the user experience.

[0096] In one embodiment of this utility model, reference is made to Figure 8 The reading circuit 2 also includes:

[0097] The signal isolation circuit 130 has its input terminal electrically connected to the nozzle connection terminal 10, and the output terminal of the filter circuit 120 is electrically connected to the voltage conversion circuit 30.

[0098] The signal isolation circuit 130 is used to isolate the identification signal and output it to the voltage conversion circuit 30.

[0099] In this embodiment, the signal isolation circuit 130 can be implemented using an optocoupler, transformer, or other similar device.

[0100] Based on the above embodiments, after receiving the read signal from the main control circuit 100, printhead 1 outputs a corresponding identification signal to printhead connection terminal 10. Signal isolation circuit 130 (such as an optocoupler) isolates the identification signal and outputs it to voltage conversion circuit 30. Voltage conversion circuit 30 then adjusts the voltage of the isolated identification signal to a first preset voltage before outputting it to second signal terminal 20. For example, it converts the 1.5V of the printhead 1 feedback information (identification signal) to 3.3V, facilitating accurate identification of printhead 1's ID information by the main control circuit 100 and adjusting parameters for printing. In this embodiment, the optocoupler in signal isolation circuit 130 achieves isolated signal transmission through photoelectric conversion. Specifically, when printhead 1 outputs an identification signal to printhead connection terminal 10, the input terminal of the optocoupler receives a corresponding first electrical signal, the LED in the optocoupler operates, and the phototransistor is activated, thereby generating a corresponding second electrical signal at the output terminal of the optocoupler. In this way, the optocoupler effectively isolates the electrical connection between the nozzle connection terminal 10 and the voltage conversion circuit 30, preventing high voltage or noise interference from being transmitted from the nozzle connection terminal 10 to the input terminal of the voltage conversion circuit 30.

[0101] It is understood that the reading circuit 2 may include the aforementioned filtering circuit 120 and signal isolation circuit 130. The input terminal of the signal isolation circuit 130 is electrically connected to the nozzle connection terminal 10, the input terminal of the filtering circuit 120 is electrically connected to the output terminal of the signal isolation circuit 130, and the output terminal of the filtering circuit 120 is electrically connected to the voltage conversion circuit 30. The signal isolated by the signal isolation circuit 130 enters the filtering circuit 120, which filters it to remove high-frequency noise, low-frequency noise, etc., and then transmits it to the voltage conversion circuit 30 to adjust its voltage to the first preset voltage before outputting it to the second signal terminal 20, so that the main control circuit 100 can accurately identify the ID information of the nozzle 1.

[0102] Through the above configuration, the signal isolation circuit 130 can effectively improve the problem of external noise and interference signals being transmitted from the printhead connection terminal 10 to the filter circuit 120 and subsequent circuits, protecting the filter circuit 120 and other circuits from interference. For example, it mitigates the damage to components in the reading circuit 2 caused by overvoltage and electrostatic discharge, extends the service life of components in the reading circuit 2, and further improves the anti-interference capability and reliability of the reading circuit 2. Furthermore, the simultaneous configuration of the signal isolation circuit 130 and the filter circuit 120 provides dual protection, minimizing signal distortion and misjudgment during transmission, improving the accuracy of the main control circuit 100 in recognizing printhead marking information, and enhancing the performance of the inkjet printing equipment.

[0103] In another embodiment, reference Figure 9 The reading circuit 2 further includes:

[0104] Impedance matching circuit 70, the first end of which is electrically connected between nozzle connection terminal 10 and voltage conversion circuit 30, and the second end of impedance matching circuit 70 is electrically connected to first signal terminal 110.

[0105] In this embodiment, the impedance matching circuit 70 can be implemented using an LC network, a buffer, and a resistor.

[0106] refer to Figure 6 The impedance matching circuit 70 includes a resistor R3. The first end of resistor R3 is electrically connected to the common terminal of the nozzle connection terminal 10 and the base of transistor Q1, and the second end of resistor R3 is connected to the first signal terminal 110. It is understood that when both the first signal terminal 110 and the second signal terminal 20 are configured as input modes, and the main control circuit 100 sets both the first and second interfaces to output modes, a read signal is output through the first interface to the first signal terminal 110, and then output to the nozzle connection terminal 10, thereby causing the nozzle connection terminal 10 to output an identification signal upon receiving the read signal. It should be noted that after the main control circuit 100 outputs the read signal, it sets both the first and second interfaces to input modes. At this time, the first signal terminal 110 and the second signal terminal 20 are also configured as output modes. To avoid inconsistent signal levels between the first signal terminal 110 and the second signal terminal 20 (e.g., one signal terminal is high and the other is low), which would prevent the main control circuit 100 from correctly identifying the identification signal, this is necessary. In this embodiment, resistor R3 serves as impedance matching and protection. Its resistance is typically less than 50Ω (e.g., 0Ω), and can be 0Ω, thus ensuring that the main control circuit 100 receives the identification signal output from the second signal terminal 20 via the second interface, thereby correctly identifying the nozzle 1's identity information. The presence of resistor R3 limits the maximum current that may flow through the first signal terminal 110, providing a certain degree of protection.

[0107] The above settings provide necessary impedance matching and safety during input / output state switching, enhancing the stability and reliability of the read circuit 2. Furthermore, they mitigate hardware damage caused by unexpected high / low level conflicts.

[0108] This utility model proposes a control board 3, as shown in the reference. Figure 1 The control board 3 includes the reading circuit 2 described in any one of the above and the main control circuit 100. The main control circuit 100 has a first interface and a second interface. The first interface is connected to the first signal terminal 110 of the reading circuit 2, and the second interface is connected to the second signal terminal 20 of the reading circuit 2. The main control circuit 100 is used to output a reading signal to the reading circuit 2 through the first interface and to receive an identification signal through the second interface.

[0109] Optionally, the first interface is an input / output interface, which has an input mode and an output mode. The first interface is used to output a read signal to the first signal terminal 110 in the output mode, and to switch to the input mode after outputting the read signal.

[0110] In this embodiment, the control board 3 can be implemented using a flexible printed circuit board (FPC), metal circuit board, ceramic circuit board, printed circuit board (PCB), etc. The main control circuit 100 can be implemented using a main controller, such as an MCU (Microcontroller Unit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), PLC (Programmable Logic Controller), SOC (System on Chip), etc.

[0111] Specifically, the reading circuit 2 communicates with the nozzle 1 and receives its identification signal, while the main control circuit 100 is responsible for controlling the entire process, outputting the reading signal, and processing the received identification signal. (Reference) Figure 6 IO1 is the first interface of the main control circuit 100, connected to the first signal terminal 110, and IO2 is the second interface of the main control circuit 100, connected to the second signal terminal 20. The main control circuit 100 can configure pin information. First, it sets both the first and second interfaces to output mode, and outputs a read signal through the first interface to the first signal terminal 110 of the read circuit 2, so as to send it to the nozzle 1 via the nozzle connection terminal 10. After the read signal is output, the main control circuit 100 configures the first and second interfaces to input mode and monitors the status changes of the second interface. For example, it detects the presence or absence of the identification signal of the second interface by means of interrupt or polling, reads and stores the identification signal returned by the nozzle 1, and parses and processes the received identification signal, including decoding the identification signal and verifying data integrity. Finally, the processed identification signal can be stored in the memory of the main control circuit 100, or sent to an external device (such as a computer) for further processing.

[0112] It should be noted that the main control circuit 100 can also control LEDs or other indicators on the inkjet printer to display the current signal status received via the second interface (IO2), such as successful or failed read. If no valid identification signal is received within a preset time, the MCU can determine that the read has failed and take corresponding measures, such as resending the read signal or reporting an error, so that the user can handle it in a timely manner and avoid inconvenience caused by the inability to print normally. In addition, if the control board 3 requires low-power operation, the MCU can enter a low-power mode to shut down unnecessary peripherals when not needed, thereby saving power.

[0113] In practical applications, after outputting the read signal, the main control circuit 100 configures both the first and second interfaces to input mode, simplifying the complexity of input / output state management for the main control circuit 100. At this time, the MCU only needs to focus on the identification signal received from the second interface (IO2) without needing to detect state changes in IO1. That is, the configuration of the main control circuit 100 and the read circuit 2 improves the accuracy of the feedback signal (identification signal) output by the printhead 1, thereby improving the reliability and stability of the inkjet printing equipment and enhancing the user experience.

[0114] It is worth noting that since the control board 3 of this application includes the above-mentioned reading circuit 2, the embodiments of the control board 3 of this application include all the technical solutions of all the embodiments of the above-mentioned reading circuit 2, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0115] This invention also proposes an inkjet printing device 4. In some embodiments, the inkjet printing device 4 includes a printhead 1 and a reading circuit 2 as described above, wherein the printhead connection terminal 10 of the reading circuit 2 is electrically connected to the printhead 1. In some embodiments, the inkjet printing device 4 includes a printhead 1 and a control board 3 as described above, wherein the printhead 1 is electrically connected to the control board 3.

[0116] In this embodiment, the inkjet printing device 4 includes consumer inkjet printers, industrial inkjet printers, color inkjet printers, etc., and the printhead 1 can be implemented using piezoelectric printheads, microelectromechanical systems (MEMS) printheads, electrostatic printheads, etc.

[0117] In some embodiments, the inkjet printing device 4 may also include other functional components, such as a printhead, a moving part, an ink supply part, etc. The printhead 1 and the reading circuit 2 may be disposed inside the printhead, the printhead may be disposed on the moving part, and the ink supply part may be connected to the printhead to supply ink to the printhead.

[0118] It is worth noting that since the inkjet printing device 4 of this application includes the above-mentioned reading circuit 2 or control board 3, the embodiments of the inkjet printing device 4 of this application include all the technical solutions of all the embodiments of the above-mentioned reading circuit 2 or control board 3, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0119] The above description is only an optional embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of the present utility model.

Claims

1. A reading circuit, characterized in that, Applied to inkjet printing equipment, the inkjet printing equipment includes a printhead and a main control circuit, and the reading circuit includes: The nozzle connection terminal is used to connect to the nozzle, send a read signal to the nozzle, and receive the identification signal output by the nozzle; The first signal terminal is connected to the nozzle connection terminal and is used to receive the read signal output by the main control circuit and output it to the nozzle connection terminal. The second signal terminal is used to connect to the main control circuit and output the identification signal; A voltage conversion circuit is connected in series between the nozzle connection terminal and the second signal terminal; The voltage conversion circuit is used to convert the voltage of the identification signal output from the nozzle connection terminal into a first preset voltage and then output it to the second signal terminal.

2. The reading circuit as described in claim 1, characterized in that, The reading circuit further includes: a power input terminal for providing the first preset voltage; the voltage conversion circuit includes: The NOT gate circuit has its first terminal electrically connected to the nozzle connection terminal, and its second terminal electrically connected to the second signal terminal and the power input terminal, respectively. The NOT gate is used to disconnect when the identification signal is received, so as to output the first preset voltage to the second signal terminal.

3. The reading circuit as described in claim 2, characterized in that, The NOT gate circuit includes: A first resistor, the first end of which is electrically connected to the power input terminal; A switching transistor, the first end of which is connected to the nozzle connection terminal, the second end of which is electrically connected to the second signal terminal and the second end of the first resistor, and the third end of which is grounded; The switching transistor is configured to: disconnect the electrical connection between the nozzle connection terminal and the second signal terminal when receiving an identification signal from the nozzle connection terminal, so as to output a first preset voltage to the second signal terminal; and, when not receiving an identification signal from the nozzle connection terminal, connect the electrical connection between the nozzle connection terminal and the second signal terminal, so as to output a second preset voltage to the second signal terminal.

4. The reading circuit as described in claim 3, characterized in that, The switching transistor includes a triode, the base of which is electrically connected to the nozzle connection terminal, the collector of which is electrically connected to the second signal terminal and the second terminal of the first resistor, and the emitter of which is grounded.

5. The reading circuit as described in claim 2, characterized in that, The reading circuit also includes: A pull-up circuit is provided, wherein the first end of the pull-up circuit is electrically connected to the power input terminal; and the second end of the pull-up circuit is electrically connected to both the nozzle connection terminal and the voltage conversion circuit. The pull-up circuit is used to pull up the voltage of the nozzle connection terminal to a first preset voltage when the identification signal is not connected to the nozzle connection terminal. The NOT gate circuit is used to conduct under the first preset voltage so that the output voltage of the second signal terminal is the second preset voltage.

6. The reading circuit as described in claim 1, characterized in that, The reading circuit also includes: A current limiting circuit, wherein the first terminal of the current limiting circuit is electrically connected to the power input terminal and the nozzle connection terminal, and the second terminal of the current limiting circuit is electrically connected to the first terminal of the voltage conversion circuit; The current limiting circuit is used to limit the current flowing to the first terminal of the voltage conversion circuit within a preset current range.

7. The reading circuit as described in claim 1, characterized in that, The reading circuit also includes: An impedance matching circuit is provided, wherein the first end of the impedance matching circuit is electrically connected between the nozzle connection terminal and the voltage conversion circuit, and the second end of the impedance matching circuit is electrically connected to the first signal terminal.

8. A control board, characterized in that, The control panel includes: The readout circuit as described in any one of claims 1 to 7; and The main control circuit has a first interface and a second interface. The first interface is connected to the first signal terminal of the reading circuit, and the second interface is connected to the second signal terminal of the reading circuit. The main control circuit is used to output a reading signal to the reading circuit through the first interface and to receive the identification signal through the second interface.

9. The control board as described in claim 8, characterized in that, The first interface is an input / output interface. The first interface has an input mode and an output mode. The first interface is used to output a read signal to the first signal terminal in the output mode, and to switch to the input mode after outputting the read signal.

10. An inkjet printing device, characterized in that, The inkjet printing device includes a printhead and a readout circuit as described in any one of claims 1 to 7, wherein the printhead connection terminal of the readout circuit is electrically connected to the printhead; or, The inkjet printing device includes a printhead and a control board as described in claim 8 or 9, wherein the printhead is electrically connected to the control board.

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