Inkjet printhead and its flexible circuit board, working method of inkjet printhead

Abstract

The present application provides an inkjet print head, a flexible circuit board thereof, and a working method of the inkjet print head. The flexible circuit board comprises a flexible substrate, a contact area is formed on a surface of the substrate, a plurality of connection terminals are arranged in the contact area, and the plurality of connection terminals are located in one plane. Among the plurality of connection terminals, only one or two connection terminals are detection connection terminals, and the detection connection terminals are used to output detection signals to an inkjet printing device for detecting a connection state between the inkjet print head and the inkjet printing device. The inkjet print head is provided with the flexible circuit board described above, and the present application further provides a working method of the inkjet print head. The present application can reduce the number of detection connection terminals located in the corner and reduce the wiring complexity of the flexible circuit board.

Description

Technical Field

[0001] This invention relates to the technical field of inkjet printing, and more specifically, to a flexible circuit board having an inkjet printhead, a flexible circuit board having such an inkjet printhead, and a method of operating such an inkjet printhead. Background Technology

[0002] An inkjet printhead is a consumable that can be installed in an inkjet printer. An inkjet printhead has a housing that forms an ink chamber to hold ink. At the lower end of the ink chamber is an ink outlet with multiple nozzles. A flexible circuit board is mounted on the outer wall of the housing to control the opening and closing of the nozzles.

[0003] See Figure 1 The flexible circuit board 10 has a flexible substrate 11, on the surface of which multiple connection terminals are provided. Because of the large number of connection terminals, the inkjet printer needs to send signals to the control circuit through these connection terminals to control the opening and closing of the nozzles. Therefore, the inkjet printer needs to detect the contact status with the connection terminals. If any connection terminal fails to maintain good contact with the inkjet printer, the inkjet operation is stopped.

[0004] Therefore, these connection terminals include three detection connection terminals, located at three corners, such as detection connection terminals 15, 16, and 17. The inkjet printer outputs signals to two of these detection connection terminals. After logical operations are performed by the internal logic circuit, a return signal is received from the third detection connection terminal. If the third detection connection terminal returns a correct signal, it is considered that the inkjet printhead has been installed correctly and all connection terminals are making good contact.

[0005] However, since the three detection connection terminals are located in three corners, especially in the corners of the flexible circuit board, they occupy corner space, which is not conducive to the installation of the flexible circuit board. Furthermore, the flexible circuit board needs to house logic operation circuitry that needs to be connected to the three detection connection terminals simultaneously, and since these three connection terminals are located in three different corners, the wiring on the flexible circuit board becomes very complex. This can also affect the wiring of other circuit modules on the flexible circuit board and even cause interference to them. Summary of the Invention

[0006] The first objective of this invention is to provide a flexible circuit board for an inkjet printhead that avoids occupying corner space and reduces the complexity of flexible circuit board wiring.

[0007] A second objective of the present invention is to provide an inkjet printhead using the aforementioned flexible circuit board.

[0008] A third objective of the present invention is to provide a method for operating the inkjet printhead described above.

[0009] To achieve the first objective mentioned above, the flexible circuit board of the inkjet printhead provided by the present invention includes a flexible substrate, a contact area is formed on the surface of the substrate, and a plurality of connection terminals are disposed in the contact area, the plurality of connection terminals being located in a plane; wherein, among the plurality of connection terminals, only one or two connection terminals are detection connection terminals, the detection connection terminals being used to output detection signals to the inkjet printing device for detecting the connection status between the inkjet printhead and the inkjet printing device.

[0010] Alternatively, the detection connection terminal may be located at at least one corner of the contact area or in the center of the contact area.

[0011] In a preferred embodiment, the substrate is further provided with a control circuit; the multiple connection terminals also include at least one data terminal, which is electrically connected to the control circuit; the data terminal is grounded through a first resistor.

[0012] A further embodiment includes at least one control signal receiving terminal, which is electrically connected to the control circuit; the control signal receiving terminal is grounded through a second resistor; or, the control signal receiving terminal is connected to the power supply through a third resistor.

[0013] A further option is to include power terminals in the multiple connection terminals, which are used to output signals to the detection connection terminals.

[0014] A further approach is to have the power terminals also supply power to the control circuitry on the substrate.

[0015] To achieve the second objective mentioned above, the inkjet printhead provided by the present invention includes a housing, an ink cavity for containing ink is formed inside the housing, and an ink outlet is formed in the housing, the ink outlet being provided with a plurality of nozzles and communicating with the ink cavity; and the aforementioned flexible circuit board is provided on the outer wall of the housing.

[0016] To achieve the third objective mentioned above, in the inkjet printhead operation method provided by the present invention, the flexible circuit board of the inkjet printhead is provided with multiple connection terminals; among the multiple connection terminals, only one or two connection terminals are detection connection terminals, and the multiple connection terminals also include power supply terminals; the method includes: after receiving the voltage provided by the inkjet printing device, the power supply terminal supplies power to the detection connection terminal, so that the detection connection terminal outputs a detection signal to the inkjet printing device for detecting the connection status between the inkjet printhead and the inkjet printing device.

[0017] In a preferred embodiment, the plurality of connection terminals further include at least one control signal receiving terminal, which is electrically connected to the control circuit; the method further includes stopping the inkjet operation when the signal of the control signal receiving terminal is abnormal.

[0018] A further solution is to stop the inkjet operation by: stopping the drive of the field-effect transistor used to open the nozzle; or limiting the ejection frequency of the nozzle.

[0019] As can be seen from the above solution, the present invention reduces the occupation of corner space on the flexible circuit board by reducing the number of detection connection terminals located in the corners. Furthermore, the power terminal can output a signal to the detection connection terminal. Thus, once the inkjet printhead is installed in the inkjet printing equipment and the inkjet printing equipment supplies power to the power terminal, the detection connection terminal outputs a detection signal to the inkjet printing equipment, thereby meeting the detection requirements of the inkjet printing equipment.

[0020] In addition, to avoid overheating of the nozzles due to abnormal contact between the connection terminals and the inkjet printing equipment, the flexible circuit board will detect the signals of each control signal receiving terminal. If the signal of a certain control signal receiving terminal is abnormal, such as a high level or low level signal for a period of time, the inkjet process will be stopped, thus stopping the nozzle heating and preventing the nozzle from burning out due to excessive temperature.

[0021] Furthermore, since the data terminal is grounded through the first resistor, if the data terminal has poor contact with the inkjet printer, the first resistor will prevent the data terminal from entering a high-resistance state and instead keep it in a low-level state. This avoids the nozzle from being falsely triggered due to the high resistance of the data terminal and effectively prevents the nozzle from overheating due to false triggering when the data terminal has poor contact with the inkjet printer. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a flexible circuit board for an existing inkjet printhead.

[0023] Figure 2 This is a schematic diagram of the first embodiment of the flexible circuit board of the inkjet printhead of the present invention.

[0024] Figure 3 This is a schematic diagram showing the connection between the temperature detection terminal and the grounding terminal of the first embodiment of the flexible circuit board of the inkjet printhead of the present invention.

[0025] Figure 4 This is a schematic diagram of the connection terminals of the detection connection terminal in the first embodiment of the flexible circuit board of the inkjet printhead of the present invention.

[0026] Figure 5This is an electrical schematic diagram of the control circuit of the first embodiment of the flexible circuit board of the inkjet printhead of the present invention.

[0027] Figure 6 This is a flowchart of an embodiment of the working method of the inkjet printhead of the present invention.

[0028] Figure 7 This is a schematic diagram of the second embodiment of the flexible circuit board of the inkjet printhead of the present invention.

[0029] Figure 8 This is a schematic diagram of the third embodiment of the flexible circuit board of the inkjet printhead of the present invention.

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0031] First embodiment: In this embodiment, the inkjet printhead is detachably mounted onto an inkjet printer. The printhead has a housing that encloses an ink chamber containing ink. An ink outlet is located at the lower end of the housing, and multiple nozzles are provided at the ink outlet. The ink outlet is connected to the ink chamber, allowing ink to be ejected from the ink outlet. Furthermore, each nozzle is equipped with a heating element controlled by a field-effect transistor (FET). For example, when the FET is in the ON state, the heating element is energized and heats up, causing ink to flow from the nozzle; when the FET is in the OFF state, the heating element is not energized and does not heat up.

[0032] A flexible circuit board is mounted on the outer wall of the inkjet printhead housing. (See...) Figure 2 The flexible circuit board 20 of this embodiment has a flexible substrate 21. The substrate 21 can be bent. Therefore, the substrate 21 can be disposed on two different surfaces of the housing. For example, a part of the flexible circuit board 20 is disposed on the bottom wall of the housing, and another part is disposed on the front wall of the housing.

[0033] The substrate 21 is provided with multiple connection terminals, which are located on the contact area of ​​the flexible circuit board 20. The contact area is the area where it connects with the inkjet printing device. Specifically, the inkjet printing device is also provided with multiple pins. When the inkjet printhead is installed in the inkjet printing device, each pin contacts a connection terminal, thereby realizing communication between the inkjet printing device and the inkjet printhead. The inkjet printing device provides power, clock signals, data signals, etc. to the inkjet printhead through the pins, and receives signals returned by the inkjet printhead.

[0034] Among the multiple connection terminals, there are one or two detection connection terminals. For example, in this embodiment, only two detection connection terminals are provided, namely detection connection terminal 26 and detection connection terminal 27. Detection connection terminal 26 is located in the second row, and detection connection terminal 27 is located in the fourth row. Neither detection connection terminal 26 nor 27 is located at the corner of the contact area. It can be understood that both detection connection terminals 26 and 27 are located at the center of the contact area, which is a position other than the four corners. Placing the detection connection terminals at the center of the contact area can ensure the reliability of contact between the detection connection terminals and the inkjet printing device, thereby ensuring the reliability of the transmission of detection signals.

[0035] Of course, in other embodiments, the two detection connection terminals can also be located at the corners of the contact area, for example, one detection connection terminal is located at the upper left corner of the contact area, and the other detection connection terminal is located at the lower left corner of the contact area. Compared with existing inkjet printheads, this embodiment reduces one detection connection terminal, for example, by not setting a detection connection terminal at the upper right corner, or by not setting detection connection terminals at any of the three corners. This avoids occupying the space in the upper right corner of the flexible circuit board, which can be used for circuit wiring or setting circuit modules, etc., facilitating the circuit layout of the flexible circuit board.

[0036] For example, the temperature sensing terminal PT and the grounding terminal GND can be used together as the sensing connection terminal, or only one of the temperature sensing terminal PT or the grounding terminal GND can be used as the sensing connection terminal. If the temperature sensing terminal PT and the grounding terminal GND are used together as the sensing connection terminal, such as... Figure 3 As shown, a diode D1 is connected between the temperature sensing terminal 35 and the ground terminal 36. After the inkjet printhead is installed in the inkjet printer, the flexible circuit board of the inkjet printer outputs a power signal of approximately 3.3V, which is used to power the temperature sensing terminal 35. When the inkjet printer detects the voltage of the temperature sensing terminal 35, due to the presence of diode D1, the temperature sensing terminal 35 will not present a 0V voltage; that is, it will output a voltage higher than 0V. When the inkjet printer detects the voltage output by the temperature sensing terminal 35, it considers that the inkjet printhead has been correctly installed.

[0037] Since the inkjet printer needs to receive a signal from one of the detection connection terminals to determine whether the inkjet printhead has been installed in the inkjet printer and is making good contact, this embodiment requires a detection signal to be returned to the inkjet printer through one of the detection connection terminals. Alternatively, a detection signal can be returned to the inkjet printer through detection connection terminal 26.

[0038] Furthermore, among the multiple connection terminals, there is also a power terminal. The power electronics can receive power from the inkjet printer. The received power may be a 3.3V DC power supply or a 24V DC power supply. In this embodiment, the power received from the power terminal is converted and then output to the detection connection terminal 26. See also... Figure 4 After receiving DC power from the inkjet printer, power terminal 31 processes the power supply signal through power processing circuit 33 to generate an electrical signal that meets the requirements of the inkjet printer, thus forming a detection signal that is returned to the inkjet printer. In one scenario, the voltage received by power terminal 31 is 24V, while the voltage requirement returned to the inkjet printer from detection terminal 26 is 3.3V. Therefore, power processing circuit 33 is essentially a step-down circuit, converting the 24V DC voltage to 3.3V DC voltage. Of course, power processing circuit 33 can also include filtering circuits and voltage regulator circuits to make the DC voltage output from detection terminal 26 more stable. Power processing circuit 33 can be implemented using known circuits, which will not be elaborated here.

[0039] Once the inkjet printhead is installed in the inkjet printer, as long as the inkjet printer supplies power to the power terminal 31, the detection connection terminal 26 will output a detection signal. The inkjet printer can then receive the detection signal and consider that the inkjet printhead has been correctly installed, thereby verifying the installation of the inkjet printhead.

[0040] As can be seen, this embodiment does not require three detection connection terminals, and the flexible circuit board does not contain any logic circuits for performing logic operations on the signals received by two of the detection connection terminals. Thus, there is no need to set up logic circuits on the flexible circuit board, let alone set up lines connecting the detection connection terminals and the logic circuits. Therefore, there is no need to set up very complex wiring lines on the flexible circuit board, which can reduce the design difficulty of the flexible circuit board, reduce the manufacturing difficulty of the flexible circuit board, and thus reduce the production cost of the flexible circuit board.

[0041] Since the detection connection terminal 26 in this embodiment is only used to return a detection signal to the inkjet printing device, the detection connection terminal 27 may not actually receive signals from the inkjet printing device. In other embodiments, only one detection connection terminal may be provided on the flexible circuit board, for example, only the detection connection terminal 26 may be provided, and the detection connection terminal 27 may not be provided.

[0042] Since this embodiment only sets one or two detection connection terminals, even if the detection connection terminal 26 sends a detection signal to the inkjet printer, there is still a possibility that the flexible circuit board may not be in complete contact with the inkjet printer. For example, only some connection terminals on the flexible circuit board may be in good contact with the inkjet printer, while others may not be. If the inkjet printer considers the inkjet printhead to be properly installed and sends a signal to control the inkjet operation, but there are multiple connection terminals on the inkjet printhead that are not in contact, it can easily lead to abnormal nozzle control. For example, nozzles that should be open may not be open, or nozzles that should be closed may not be closed, resulting in printing errors, such as spraying too much or too little ink, affecting print quality.

[0043] In one specific scenario, if the data terminal among the multiple connection terminals does not make good contact with the inkjet printer, the data terminal will be in a floating state, that is, the data terminal is in a high-resistance state. This is an uncertain state, and the data terminal may be in a high-level state or a low-level state, which will cause the nozzle to open or close abnormally.

[0044] See Figure 5 A control circuit 40 is provided on the flexible circuit board, and a data terminal 41 can output signals to the control circuit 40. When the data terminal 41 outputs a set of control signals containing timing logic, the control circuit 40 will determine which nozzles need to be opened and which nozzles need to be closed based on this set of control signals. During inkjet printing, the control circuit 40 will also control the on / off state of the field-effect transistor Q1 based on signals obtained from the data terminal 41 and other connection terminals 42, 43, etc. One end of the field-effect transistor Q1 is connected to the DC power supply VDD, and the other end is connected to the resistor R4, which serves as a heating element. When the field-effect transistor Q1 is turned on, the resistor R4 is energized and heats up; when the field-effect transistor Q1 is turned off, the resistor R4 is not energized.

[0045] As mentioned earlier, if there is a connection error at data terminal 41, some nozzles will open or close abnormally. Furthermore, if data terminal 41 abnormally reaches a high level, the field-effect transistor Q1 will abnormally enter the conducting state, causing resistor R4 to overheat abnormally, which may lead to the nozzle burning out.

[0046] To address this issue, this embodiment adds a grounded first resistor R1 at the connection between the data terminal 41 and the control circuit 40. That is, the data terminal 41 is grounded through the first resistor R1. When the data terminal 41 is in a floating state, the presence of the first resistor R1 causes the signal received by the control circuit 40 to be at a low level. In other words, the data signal received by the control circuit 40 is a low-level signal. As a result, all the field-effect transistors corresponding to the nozzles are in a cutoff state, and the heating elements of all nozzles will not heat up or operate, thus avoiding the problem of nozzle burnout due to poor contact between the data terminal 41 and the inkjet printing equipment.

[0047] Correspondingly, for the control signal receiving terminal 42 connected to the control circuit 40, since the control signal receiving terminal 42 should output a low-level signal to the control circuit 40 in standby mode, the control signal receiving terminal 42 needs to be grounded through the second resistor R2; for the control signal receiving terminal 43 connected to the control circuit 40, since the control signal receiving terminal 43 should output a high-level signal to the control circuit 40 in standby mode, the control signal receiving terminal 43 needs to be connected to the power supply VDD through the third resistor R3. In this way, if the data terminal 41 or the control signal receiving terminals 42 and 43 have poor contact with the inkjet printer, the signal received by the control circuit 40 will be the same as the signal received in standby mode. For example, if the control signal receiving terminal 42 outputs a continuous low-level signal to the control circuit 40, while the control signal receiving terminal 43 outputs a continuous high-level signal to the control circuit 40, the control circuit 40 will consider that there is an abnormality in the control signal receiving terminal, and will not open the corresponding nozzle, thus preventing the heating element from accidentally heating and damaging the nozzle, and preventing the nozzle from opening or closing unexpectedly and affecting the print quality.

[0048] The following is combined Figure 6 The working process of the inkjet printhead is described below. First, in step S11, the inkjet printer supplies power to the flexible circuit board. At this time, the power terminal will receive the DC power provided by the inkjet printer. The power terminal will then output the received DC voltage to the power processing circuit, which will process the DC voltage, such as by stepping down, stabilizing, and filtering, before outputting it to the detection connection terminal.

[0049] Next, step S12 is executed, detecting that the connection terminals output a detection signal to the inkjet printer, such as a continuous high-level signal. This indicates that the inkjet printer considers the printhead to be properly installed and that all connection terminals are making good contact with the inkjet printer's pins, enabling inkjet printing operations.

[0050] Then, the control circuit of the flexible circuit board needs to execute step S13 to determine whether the signal of the control signal receiving terminal is abnormal, such as a continuous high-level or low-level signal. A continuous high-level or low-level signal means that the control signal receiving terminal only outputs a high-level signal or only outputs a low-level signal for a preset period of time. If so, it indicates that the control signal receiving terminal is not making good contact with the inkjet printing device, resulting in a continuous high-level or continuous low-level signal. At this time, step S14 needs to be executed to stop the inkjet printing operation. Specifically, the control circuit will stop driving the field-effect transistor used to open the nozzle, or limit the nozzle ejection frequency, that is, limit the opening frequency of the field-effect transistor. For example, setting the opening frequency of the field-effect transistor to 0 is equivalent to prohibiting the field-effect transistor from being in the conducting state. In this way, it is possible to avoid the situation where the field-effect transistor is opened due to abnormal connection of the connection terminal of the flexible circuit board, which could lead to damage to the nozzle.

[0051] If the result of step S13 is negative, it means that there is no abnormality in the signal of the control signal receiving terminal. Step S15 will be executed. The control circuit will control the operation of the field-effect transistors corresponding to each nozzle according to the signal output from the control signal receiving terminal and the signal output from the data terminal, thereby realizing the inkjet printing operation.

[0052] Finally, proceed to step S16 to determine whether the inkjet printer has stopped receiving power, that is, to determine whether the inkjet printer has lost power. If it has lost power, the operation ends. If it has not lost power, return to step S13 to continue to determine whether there is any abnormality in the signal of the control signal receiving terminal.

[0053] As can be seen, this invention only sets one or two detection connection terminals on the flexible circuit board of the inkjet printhead, and does not set logic circuits, which can reduce the wiring difficulty of the flexible circuit board and avoid occupying the corner space of the flexible circuit board, which is more conducive to the wiring of the flexible circuit board. In addition, after reducing the number of detection connection terminals, in order to detect the connection status of multiple connection terminals, especially the connection status of multiple control signal receiving terminals, pull-up resistors or pull-down resistors are set on the data terminals and control signal receiving terminals. When the data terminals or control signal receiving terminals have abnormal connections, they output a continuous high-level signal or a continuous low-level signal to indicate that the terminal has abnormal connections. The control circuit then stops the inkjet printing operation, thereby avoiding the situation of nozzle burn-out and also avoiding print quality problems caused by incorrect nozzle opening.

[0054] Second embodiment: In this embodiment, the inkjet printhead is detachably mounted onto an inkjet printing device. The inkjet printhead has a housing that encloses an ink chamber containing ink. A flexible circuit board is disposed on the outer wall of the inkjet printhead housing. (See attached image.) Figure 7 The flexible circuit board 50 of this embodiment has a flexible substrate 51, which can be bent. Therefore, the substrate 51 can be disposed on two different surfaces of the housing.

[0055] The substrate 51 has multiple connection terminals located on the contact area of ​​the flexible circuit board 50, and these terminals include two detection connection terminals, such as detection connection terminal 56 and detection connection terminal 57. Furthermore, a temperature detection terminal PT and a ground terminal GND can be reused as the detection connection terminals. Unlike existing inkjet printheads, in this embodiment, the connection terminal 55 located in the upper right corner is merely a copper foil and is not connected to any circuitry or electronic module on the substrate 51. Therefore, connection terminal 55 can be considered an electrically isolated terminal.

[0056] Third embodiment: In this embodiment, the inkjet printhead is detachably mounted onto an inkjet printing device. The inkjet printhead has a housing that encloses an ink chamber containing ink. A flexible circuit board is disposed on the outer wall of the inkjet printhead housing. (See attached image.) Figure 8 The flexible circuit board 60 of this embodiment has a flexible substrate 61, which can be bent. Therefore, the substrate 61 can be disposed on two different surfaces of the housing.

[0057] The substrate 61 is provided with a plurality of connection terminals located on the contact area of ​​the flexible circuit board 60, and the plurality of connection terminals include two detection connection terminals, such as detection connection terminal 66 and detection connection terminal 67. Unlike the second embodiment, in this embodiment, the connection terminal 65 located in the upper right corner and the connection terminal 68 located in the lower right corner are not connected to any circuit or electronic module on the substrate 61. Therefore, it can be considered that the connection terminal 65 and the connection terminal 68 are electrically isolated terminals, only having the shape of connection terminals.

[0058] Finally, it should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible circuit board for an inkjet printhead, including: A flexible substrate, wherein a contact area is formed on the surface of the substrate, and a plurality of connection terminals are disposed in the contact area, the plurality of connection terminals being located in a plane; Its features are: Of the plurality of connection terminals, only one or two of the connection terminals are detection connection terminals, which are used to output detection signals to the inkjet printing device to detect the connection status between the inkjet printhead and the inkjet printing device.

2. The flexible circuit board of the inkjet printhead according to claim 1, characterized in that: The substrate is also provided with a control circuit; The plurality of connection terminals also include at least one data terminal, the data terminal being electrically connected to the control circuit; The data terminal is grounded through a first resistor.

3. The flexible circuit board of the inkjet printhead according to claim 2, characterized in that: The plurality of connection terminals further include at least one control signal receiving terminal, which is electrically connected to the control circuit; The control signal receiving terminal is grounded through a second resistor; or, the control signal receiving terminal is connected to the power supply through a third resistor.

4. The flexible circuit board of the inkjet printhead according to any one of claims 1 to 3, characterized in that: The plurality of connection terminals also include a power supply terminal for outputting a signal to the detection connection terminal.

5. The flexible circuit board of the inkjet printhead according to claim 4, characterized in that: The power terminal also supplies power to the control circuitry on the substrate.

6. The flexible circuit board of the inkjet printhead according to any one of claims 1 to 3, characterized in that: The detection connection terminal is located at at least one corner of the contact area or in the center of the contact area.

7. An inkjet printhead, including a housing, wherein an ink cavity for containing ink is formed inside the housing, and the housing also has an ink outlet, wherein the ink outlet is provided with a plurality of nozzles and the ink outlet communicates with the ink cavity; Its features are: The outer wall of the housing is provided with a flexible circuit board as described in any one of claims 1 to 6.

8. The working method of the inkjet printhead, wherein the flexible circuit board of the inkjet printhead is provided with multiple connection terminals; Its features are: Of the plurality of connection terminals, only one or two of the connection terminals are detection connection terminals, and the plurality of connection terminals also include power supply terminals; The method includes: After receiving the voltage provided by the inkjet printing device, the power terminal supplies power to the detection connection terminal, so that the detection connection terminal outputs a detection signal to the inkjet printing device to detect the connection status between the inkjet printhead and the inkjet printing device.

9. The method of operating the inkjet printhead according to claim 8, characterized in that: The plurality of connection terminals further include at least one control signal receiving terminal, which is electrically connected to the control circuit; The method also includes: When the signal at the control signal receiving terminal is abnormal, the inkjet operation is stopped.

10. The method of operating the inkjet printhead according to claim 9, characterized in that: Stopping inkjet printing includes one of the following: Stop driving the field-effect transistor used to open the nozzle; Limit the spray frequency of the nozzle.

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