Print head control circuit and printer

Abstract

The present invention discloses a nozzle control circuit and a printer, wherein the nozzle control circuit comprises: a nozzle power supply circuit and a power failure detection automatic discharge circuit; the nozzle power supply circuit supplies power to the nozzle and the power failure detection automatic discharge circuit; the power failure detection automatic discharge circuit receives a first reference voltage transmitted by the nozzle power supply circuit, and releases the electric energy of the high-voltage end of the nozzle according to the voltage change of the first reference voltage when the nozzle power supply circuit fails, so as to reduce the falling time of the voltage of the high-voltage end of the nozzle. The present invention has the advantages of low cost and can protect the nozzle from being damaged.

Description

Technical Field

[0001] The present invention relates to the field of printing technology, and in particular to a nozzle control circuit and a printer. Background Art

[0002] In the field of printers, nozzle power supply is a very important technology. The printer includes a nozzle and a nozzle control circuit that controls the power supply of the nozzle. The nozzle control circuit supplies power to the high-voltage end and the low-voltage end of the nozzle respectively. When the nozzle is working, the voltage at the low-voltage end of the nozzle needs to rise before the voltage at the high-voltage end of the nozzle during the power-on process, and the voltage at the low-voltage end of the nozzle needs to drop after the voltage at the high-voltage end of the nozzle when the power is off. Such a circuit meets the normal use conditions of the nozzle, can protect the nozzle from damage and extend the service life of the nozzle.

[0003] However, in the existing nozzle control circuit, the high-voltage and low-voltage ends of the nozzle are directly connected to the power supply voltage. When the power is cut off, the voltages on the high-voltage and low-voltage ends of the nozzle drop directly, and the voltage on the low-voltage end of the nozzle drops before the voltage on the high-voltage end of the nozzle, or there is still residual voltage on the high-voltage end of the nozzle after the voltage on the low-voltage end of the nozzle drops. This power-off state cannot meet the power-off requirements of the nozzle and may easily cause damage to the nozzle. Since the repair cost of a damaged nozzle is high, how to solve the power-off timing control of the nozzle circuit has become an urgent problem for technicians in this field. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a nozzle control circuit which has low cost and can protect the nozzle from being damaged when power is off.

[0005] On the one hand, the present invention discloses a nozzle control circuit, which includes: a nozzle power supply circuit and a power-off detection automatic discharge circuit; the nozzle power supply circuit supplies power to the nozzle and the power-off detection automatic discharge circuit; the power-off detection automatic discharge circuit receives a first reference voltage transmitted by the nozzle power supply circuit, and releases the electrical energy at the high-voltage end of the nozzle according to the voltage change of the first reference voltage when the nozzle power supply circuit loses power.

[0006] Preferably, the power-off detection automatic discharge circuit includes a reference voltage setting circuit, a switching circuit and a power-off discharge circuit. The reference voltage setting circuit receives the first reference voltage transmitted from the nozzle power supply circuit and outputs a reference voltage. The switching circuit receives the reference voltage transmitted from the reference voltage setting circuit and outputs a second reference voltage when the nozzle power supply circuit loses power. The power-off discharge circuit receives the second reference voltage transmitted from the switching circuit and releases the electrical energy at the high-voltage end of the nozzle.

[0007] Preferably, the reference voltage setting circuit comprises a first capacitor, a first end of the first capacitor is electrically connected to the nozzle power supply circuit and the switch circuit, and a second end of the first capacitor is grounded.

[0008] Preferably, the reference voltage setting circuit also includes a first resistor, a second resistor and a voltage stabilizing module, the first end of the first resistor is electrically connected to the nozzle power supply circuit, the second end of the first resistor is electrically connected to the first end of the second resistor, the first end of the second resistor is electrically connected to the third end of the voltage stabilizing module, and the second end of the second resistor is grounded; the first end of the voltage stabilizing module is electrically connected to the nozzle power supply circuit and the first end of the first capacitor, and the second end of the voltage stabilizing module is grounded.

[0009] Preferably, the switching circuit includes a first transistor and a third resistor, the emitter of the first transistor is electrically connected to the first end of the first capacitor, the base of the first transistor is electrically connected to the first end of the third resistor, the collector of the first transistor is electrically connected to the power-off discharge circuit, and the second end of the third resistor is electrically connected to the high-voltage end of the nozzle.

[0010] Preferably, the power-off discharge circuit includes a second transistor, a first field effect transistor and a fourth resistor, the collector of the second transistor is electrically connected to the switching circuit, the base of the second transistor is electrically connected to the first end of the fourth resistor; the emitter of the second transistor is grounded, the gate of the first field effect transistor is electrically connected to the collector of the second transistor, the drain of the first field effect transistor is electrically connected to the high voltage end of the nozzle, the source of the first field effect transistor is electrically connected to the first end of the fourth resistor; the second end of the fourth resistor is grounded.

[0011] Preferably, the nozzle power supply circuit comprises an adjustable step-down module, and the adjustable step-down module receives the power supply voltage and outputs a third reference voltage to the low-voltage end of the nozzle.

[0012] Preferably, the nozzle power supply circuit further includes a second field effect transistor, a source of the second field effect transistor receives the power supply voltage, and a drain of the second field effect transistor outputs the first reference voltage to the power-off detection automatic power-off discharge circuit.

[0013] Preferably, the nozzle power supply circuit further includes a third transistor and a power-off detection module, the base of the third transistor receives the power supply voltage, the emitter of the third transistor is grounded, and the collector of the third transistor outputs a first control voltage to the power-off detection module. The power-off detection module includes an editable gate logic unit and a fourth transistor, the editable gate logic unit receives the first control voltage and outputs a second control voltage to the fourth transistor, the base of the fourth transistor receives the second control voltage, the collector of the fourth transistor outputs a third control voltage to the gate of the second field effect transistor, and the emitter of the fourth transistor is grounded.

[0014] On the other hand, the present invention further discloses a printer, comprising a nozzle and a nozzle control circuit for controlling the nozzle, wherein the nozzle control circuit is the nozzle control circuit described in any one of the first aspects.

[0015] The nozzle control circuit and printer of the present invention have the following beneficial effects: the printer comprises the nozzle and the nozzle control circuit, the nozzle control circuit comprises the nozzle power supply circuit and the power-off detection automatic power-off discharge circuit, the nozzle power supply circuit supplies power to the nozzle and the power-off detection automatic power-off discharge circuit during the power-on process of the printer, the power-off detection automatic power-off discharge circuit releases the electric energy at the high-voltage end of the nozzle during the power-off process of the nozzle, so as to reduce the voltage drop time of the high-voltage end of the nozzle, so that the voltage at the high-voltage end of the nozzle drops before the voltage at the low-voltage end of the nozzle; thus, the nozzle can be protected from damage when the power is off. In addition, the circuit structure is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A circuit diagram of a first embodiment of the present invention when the nozzle control circuit cooperates with the nozzle;

[0017] Figure 2 This is a circuit diagram of a second embodiment of the present invention when the nozzle control circuit cooperates with the nozzle. DETAILED DESCRIPTION

[0018] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that, if there is no conflict, the embodiments of the present invention and the various features in the embodiments can be combined with each other, all within the protection scope of the present invention.

[0019] Embodiment 1

[0020] See also Figure 1The present invention discloses a nozzle control circuit for controlling the operation of the nozzle, wherein the nozzle includes a high voltage terminal VH and a low voltage terminal VCC, and the nozzle control circuit includes: a nozzle power supply circuit 1 and a power failure detection automatic discharge circuit 2; the nozzle power supply circuit 1 supplies power to the nozzle P and the power failure detection automatic discharge circuit 2; the power failure detection automatic discharge circuit 2 receives a first reference voltage transmitted by the nozzle power supply circuit 1, and releases the electric energy of the high voltage terminal VH of the nozzle P according to the voltage change of the first reference voltage when the nozzle power supply circuit 1 is powered off, so as to reduce the falling time of the voltage of the high voltage terminal VH of the nozzle P.

[0021] In the present embodiment, the nozzle power supply circuit 1 includes an adjustable step-down module N and a third transistor K1. When the power supply voltage VIN reaches a preset value during the power-on process of the nozzle power supply circuit 1, the adjustable step-down module N starts to work and outputs the third reference voltage to the low-voltage end VCC and the first port M; in the present embodiment, the emitter of the third transistor K1 is electrically connected to the low-voltage end VCC through an eleventh resistor R11, the base of the third transistor K1 is electrically connected to the power supply through a twelfth resistor R12, and a thirteenth resistor R13 is connected between the base and the emitter of the third transistor K1. The thirteenth resistor R13 is used to lower the voltage of the third transistor K1, reduce interference, and avoid the third transistor K1 from being mistakenly opened when it needs to be closed.

[0022] The nozzle power supply circuit 1 also includes a power failure detection module 11, which includes a programmable gate logic unit F and a fourth transistor K2. The collector of the third transistor K1 outputs a first control voltage to the programmable gate logic unit F. The programmable gate logic unit F receives the first control voltage and outputs a second control voltage to the fourth transistor K2. The base of the fourth transistor K2 receives the second control voltage. The emitter of the fourth transistor K2 is grounded. The collector of the fourth transistor K2 outputs the third control voltage to the gate of the second field effect transistor Q4. In this embodiment, the programmable gate logic unit F is a FPGA (Field-Programmable Gate Array). Of course, the programmable logic unit F can also be a CPLD (Complex Programmable Logic Device) or the like. The programmable gate logic unit F is connected to the first port M, the second end of the programmable gate logic unit F is connected to the base of the fourth transistor K2 through the fourteenth resistor R14, the collector of the fourth transistor K2 is connected to the gate of the second field effect transistor Q4 through the seventeenth resistor R17, the base of the fourth transistor K2 is electrically connected to the first end of the fifteenth resistor R15, the second end of the fifteenth resistor is grounded, and the fifteenth resistor R15 is used to pull down the voltage of the fourth transistor K2. It can be understood that in an embodiment, the fourteenth resistor R14 and the seventeenth resistor R17 may not be provided.

[0023] The nozzle power supply circuit 1 also includes a second field effect transistor Q4. When the nozzle power supply circuit 1 is powered on, the source of the second field effect transistor Q4 receives the power supply voltage VIN, and the drain of the second field effect transistor Q4 outputs the first reference voltage to the power-off detection automatic discharge circuit 2 and the high-voltage terminal VH. In this embodiment, the second field effect transistor Q4 is turned on to provide voltage for the power-off detection automatic discharge circuit 2 when the nozzle power supply circuit 1 is powered on, and the second field effect transistor Q4 is turned off when the power is off. At this time, the high-voltage terminal VH supplies power to the power supply through the second field effect transistor Q4. In this embodiment, the model of the component used by the second field effect transistor Q4 is IRF9540. It can be understood that the model of the component used by the second field effect transistor Q4 is not specifically limited here.

[0024] The power-off detection automatic discharge circuit 2 includes a reference voltage setting circuit 21, a switch circuit 22, and a power-off discharge circuit 23. The reference voltage setting circuit 21 receives the first reference voltage transmitted from the nozzle power supply circuit 1 and outputs the reference voltage to the power-off discharge circuit 23. The reference voltage setting circuit 21 includes a first capacitor C1. The first end of the first capacitor C1 is electrically connected to the nozzle power supply circuit 1 and the switch circuit 22, and the second end of the first capacitor C1 is grounded. The first capacitor C1 receives the first reference voltage signal and charges when the nozzle power supply circuit 1 is powered on. When the nozzle power supply circuit 1 is powered off, the first capacitor C1 starts to discharge and outputs the reference voltage.

[0025] The reference voltage setting circuit 21 also includes a first resistor R1, a second resistor R2 and a voltage stabilizing module L. The first end of the first resistor R1 is electrically connected to the nozzle power supply circuit 1, the second end of the first resistor R1 is electrically connected to the first end of the second resistor R2, the first end of the second resistor R2 is electrically connected to the third end of the voltage stabilizing module L, and the second end of the second resistor R2 is grounded; the first end of the voltage stabilizing module L is electrically connected to the nozzle power supply circuit 1 and the first end of the first capacitor C1, and the second end of the voltage stabilizing module L is grounded. The reference voltage can be controlled by the cooperation of the first resistor R1, the second resistor R2 and the voltage stabilizing module L, and the output reference voltage remains stable for a period of time. In this embodiment, there is a resistor between the first end of the first resistor R1 and the nozzle power supply circuit 1. The element used in the voltage stabilizing module L is a voltage stabilizer of model KIA431. It can be understood that the voltage stabilizing module L can be replaced by other circuit elements as long as it plays a role in stabilizing and controlling the reference voltage, and no specific limitation is made here.

[0026] The switch circuit 22 includes a first transistor Q1 and a third resistor R3, wherein the emitter of the first transistor Q1 is electrically connected to the first end of the first capacitor C1, the base of the first transistor Q1 is electrically connected to the first end of the third resistor R3, the collector of the first transistor Q1 is electrically connected to the power-off discharge circuit 23, and the second end of the third resistor R3 is electrically connected to the nozzle P. The switch circuit 22 is used to control the opening and closing of the power-off discharge circuit 23, the first transistor Q1 is closed when the nozzle power supply circuit 1 is powered on, and the power-off discharge circuit 23 does not work; the first transistor Q1 is opened when the nozzle power supply circuit 1 is powered off, and the power-off discharge circuit 23 starts to work, and the third resistor R3 is used to divide the voltage to protect the switch circuit 22.

[0027] The power-off discharge circuit 23 includes a second transistor Q2, a first field effect transistor Q3 and a fourth resistor R4, the collector of the second transistor Q2 is electrically connected to the switch circuit 22, the base of the second transistor Q2 is electrically connected to the first end of the fourth resistor R4; the emitter of the second transistor Q2 is grounded, the gate of the first field effect transistor Q3 is electrically connected to the collector of the second transistor Q2, the drain of the first field effect transistor Q3 is electrically connected to the nozzle power supply circuit 1, the source of the first field effect transistor Q3 is electrically connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 is grounded.

[0028] The power-off discharge circuit 23 discharges the high-voltage terminal VH when the nozzle power supply circuit 1 is powered off to accelerate the voltage drop speed of the high-voltage terminal VH. After the gate of the first field effect transistor Q3 receives the second reference voltage, the first field effect transistor Q3 is turned on to discharge the high-voltage terminal VH. When the voltage of the high-voltage terminal VH is greater than a preset value, the second transistor Q2 is turned on, thereby avoiding excessive current in the first field effect transistor Q3.

[0029] The working principle of the present invention is: when the nozzle power supply circuit 1 is powered on, the adjustable step-down module N receives the power supply voltage VIN and outputs it to the low-voltage end VCC, the third transistor K1 is turned on to output the first control voltage to the power-off detection module 11, the power-off detection module 11 receives the first control voltage and outputs the second control voltage to the fourth transistor K2, the fourth transistor K2 receives the second control voltage and outputs the third control voltage to the second field effect transistor Q4, the second field effect transistor Q4 is turned on to receive the power supply voltage VIN and output the first reference voltage to the reference voltage setting module, and the first capacitor C1 starts to charge.

[0030] When the nozzle power supply circuit 1 is powered off, the third transistor K1 outputs the first control voltage to the power-off detection module 11, the power-off detection module 11 receives the first control voltage and outputs the second control voltage to the fourth transistor K2, the fourth transistor K2 is turned off, the second field effect transistor Q4 is turned off, the first capacitor C1 outputs the reference voltage to the first transistor Q1, the first transistor Q1 receives the reference voltage and outputs the second reference voltage to the first field effect transistor Q3, so that the first field effect transistor Q3 is turned on, and the high voltage end VH is discharged through the first field effect transistor Q3. Therefore, when the nozzle power supply circuit 1 is powered on, the low voltage end VCC voltage is established before the high voltage end VH voltage; when the nozzle power supply circuit 1 is powered off, the low voltage end VCC voltage drops after the high voltage end VH voltage, so that it can not only protect the nozzle P from being damaged during use, but also the circuit cost is low and easy to promote and use.

[0031] As can be seen from the above, since the nozzle control circuit of the present invention includes the nozzle power supply circuit 1 and the power-off detection automatic discharge circuit 2, the nozzle power supply circuit 1 supplies power to the nozzle and the power-off detection automatic discharge circuit 2 during the power-on process of the printer, and the power-off detection automatic power-off discharge circuit 2 releases the electric energy of the high-voltage end VH of the nozzle during the power-off process of the nozzle P, so as to reduce the voltage drop time of the high-voltage end VH of the nozzle P, so that the voltage of the high-voltage end VH of the nozzle drops before the voltage of the low-voltage end VCC of the nozzle; thus, the nozzle can be protected from damage when the power is off. In addition, the circuit structure is simple and the cost is low.

[0032] Embodiment 2

[0033] See also Figure 2 The structure of this embodiment is similar to that of the first embodiment, and the main difference is that the nozzle control circuit also includes a first filter capacitor C2, a second filter capacitor C3 and a sixteenth resistor R16, and the power-off detection circuit includes a diode D, an eighteenth resistor R18, a nineteenth resistor R19 and a twentieth resistor R20.

[0034] The first end of the first filter capacitor C2 is electrically connected to the power supply and the adjustable step-down module N, and the second end of the first filter capacitor C2 is grounded; the first end of the second filter capacitor C3 is electrically connected to the drain of the second field effect transistor Q4 and the high voltage terminal VH, and the second end of the second filter capacitor C3 is grounded. The first filter capacitor C2 is used to filter the power supply voltage VIN received by the adjustable step-down module N, and the second filter capacitor C3 is used to filter the first reference voltage received by the high voltage terminal VH.

[0035] The first end of the sixteenth resistor R16 is electrically connected to the source of the second field effect transistor Q4, and the second end of the sixteenth resistor R16 is electrically connected to the gate of the second field effect transistor Q4. The sixteenth resistor R16 is used to pull down the voltage and reduce interference.

[0036] The anode of the diode D is electrically connected to the drain of the second field effect transistor Q4, and the cathode of the diode D is electrically connected to the first end of the first resistor R1, the first end of the voltage stabilizing module L and the first end of the first capacitor C1; in the present embodiment, when the nozzle control circuit is powered on, the first capacitor C1 receives the first reference voltage through the diode D and starts to charge; when the nozzle control circuit is powered off, the first capacitor C1 starts to discharge, the diode D is unidirectionally conducted, and the switch circuit 22 receives the reference voltage.

[0037] The first end of the eighteenth resistor R18 is electrically connected to the collector of the first transistor Q1, the second end of the eighteenth resistor R18 is electrically connected to the collector of the second transistor Q2 and the gate of the first field effect transistor Q3, the first end of the nineteenth resistor R19 is electrically connected to the second end of the fourth resistor R4 and the source of the first field effect transistor Q3, the second end of the nineteenth resistor R19 is electrically connected to the emitter of the second transistor Q2, the first end of the twentieth resistor R20 is electrically connected to the collector of the second transistor Q2, and the second end of the twentieth resistor R20 is electrically connected to the emitter of the second transistor Q2. The current value of the discharge of the first field effect transistor Q3 can be set by setting the resistance values ​​of the fourth resistor R4 and the nineteenth resistor R19, so as to accurately control the voltage level of the high voltage terminal VH.

[0038] Embodiment 3

[0039] The present invention also discloses a printer, which includes a nozzle and a nozzle control circuit for controlling the nozzle. The nozzle control circuit may be the nozzle control circuit described in the first or second embodiment. For detailed description, please refer to the first and second embodiments, which will not be described here. In this embodiment, the nozzle control circuit of this embodiment has the same structure as the nozzle control circuit described in the first embodiment, and thus has the same technical effect.

[0040] The nozzle control circuit and printer provided by the present invention are described in detail above. The principle and implementation mode of the present invention are described in this article by using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification is only the implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention. It should not be understood as a limitation of the present invention.

Claims

1. A nozzle control circuit, characterized in that: include: Printhead power supply circuit and power failure detection automatic discharge circuit; The nozzle power supply circuit supplies power to the nozzle and the power-off detection automatic discharge circuit; the power-off detection automatic discharge circuit receives a first reference voltage transmitted from the nozzle power supply circuit, and releases the electric energy at the high-voltage end of the nozzle according to the voltage change of the first reference voltage when the nozzle power supply circuit is powered off; the power-off detection automatic discharge circuit includes a reference voltage setting circuit, a switch circuit and a power-off discharge circuit, the reference voltage setting circuit receives the first reference voltage transmitted from the nozzle power supply circuit and outputs a reference voltage, the switch circuit receives the reference voltage transmitted from the reference voltage setting circuit and outputs a reference voltage when the nozzle power supply circuit is powered off. When the power circuit is powered off, the second reference voltage is outputted, and the power-off discharge circuit receives the second reference voltage transmitted by the switch circuit and releases the electric energy of the high-voltage end of the nozzle; the reference voltage setting circuit also includes a first capacitor, a first resistor, a second resistor and a voltage stabilizing module, the first end of the first resistor is electrically connected to the nozzle power supply circuit, the second end of the first resistor is electrically connected to the first end of the second resistor, the first end of the second resistor is electrically connected to the third end of the voltage stabilizing module, and the second end of the second resistor is grounded; the first end of the voltage stabilizing module is electrically connected to the nozzle power supply circuit and the first end of the first capacitor, The second end of the voltage stabilizing module is grounded; the switching circuit includes a first transistor and a third resistor, the emitter of the first transistor is electrically connected to the first end of the first capacitor, the base of the first transistor is electrically connected to the first end of the third resistor, the collector of the first transistor is electrically connected to the power-off discharge circuit, and the second end of the third resistor is electrically connected to the high-voltage end of the nozzle; the power-off discharge circuit includes a second transistor, a first field effect transistor and a fourth resistor, the collector of the second transistor is electrically connected to the switching circuit, the base of the second transistor is electrically connected to the first end of the fourth resistor; the emitter of the second transistor The first field effect tube is grounded, the gate of the first field effect tube is electrically connected to the collector of the second triode, the drain of the first field effect tube is electrically connected to the high voltage end of the nozzle, and the source of the first field effect tube is electrically connected to the first end of the fourth resistor; the second end of the fourth resistor is grounded; the nozzle power supply circuit includes an adjustable step-down module, the adjustable step-down module receives the power supply voltage and outputs a third reference voltage to the low voltage end of the nozzle; the nozzle power supply circuit also includes a second field effect tube, the source of the second field effect tube receives the power supply voltage, and the drain of the second field effect tube outputs the first reference voltage to the power-off detection automatic discharge circuit; The nozzle control circuit also includes a first filter capacitor, a second filter capacitor and a sixteenth resistor; the first end of the first filter capacitor is electrically connected to the power supply and the adjustable step-down module, and the second end of the first filter capacitor is grounded; the first end of the second filter capacitor is electrically connected to the drain of the second field effect transistor and the high voltage end, and the second end of the second filter capacitor is grounded; the first end of the sixteenth resistor is electrically connected to the source of the second field effect transistor, and the second end of the sixteenth resistor is electrically connected to the gate of the second field effect transistor.

2. The nozzle control circuit according to claim 1, characterized in that: A first end of the first capacitor is electrically connected to the nozzle power supply circuit and the switch circuit, and a second end of the first capacitor is grounded.

3. The nozzle control circuit according to claim 1, characterized in that: The nozzle power supply circuit also includes a third transistor and a power-off detection module, the base of the third transistor receives the power supply voltage, the emitter of the third transistor is grounded, and the collector of the third transistor outputs a first control voltage to the power-off detection module; the power-off detection module includes an editable gate logic unit and a fourth transistor, the editable gate logic unit receives the first control voltage and outputs a second control voltage to the fourth transistor, the base of the fourth transistor receives the second control voltage, the collector of the fourth transistor outputs a third control voltage to the gate of the second field effect transistor, and the emitter of the fourth transistor is grounded.

4. A printer, comprising a nozzle and a nozzle control circuit for controlling the nozzle, characterized in that: The nozzle control circuit is the nozzle control circuit according to any one of claims 1 to 3.

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