Ink circulation system

1. An ink circulation system, comprising:

an ink cartridge, having an output pipeline and an ink cartridge valve, wherein the ink cartridge valve is disposed on the output pipeline;

an ink tank, disposed on one side of the ink cartridge and connected to the output pipeline of the ink cartridge;

an ink pump, connected to the output pipeline and the ink tank through an ink pipeline;

a first valve, connected to the ink tank through a first pipeline;

a second valve, disposed on the output pipeline;

a third valve, connected to the output pipeline and the ink pipeline through a return pipeline;

a printer head, connected to the ink tank and the return pipeline;

a heating assembly, disposed in the ink tank; and

a positive-negative pressure assembly, connected to the first pipeline through a gas pressure pipeline,

wherein the ink pump is used to extract ink from the ink cartridge and fill the ink into the ink tank along the output pipeline and the ink pipeline, and the positive-negative pressure assembly provides a positive pressure or a negative pressure to the ink tank to squeeze or absorb the ink in the ink tank,

wherein the positive-negative pressure assembly has a positive pressure pump, a negative pressure pump, and a gas pressure valve, the positive pressure pump and the negative pressure pump are respectively connected to the gas pressure pipeline, the gas pressure valve is disposed between the gas pressure pipeline and the first pipeline, and the gas pressure valve is used to switch the first pipeline to be connected to the positive pressure pump or the negative pressure pump.

2. The ink circulation system of claim 1 , wherein when the ink circulation system is in a ink filling mode, an ink volume of the ink cartridge is detected, the first valve and the ink cartridge valve are opened and the second valve is closed, the ink pump is activated to fill the ink into the ink tank along the output pipeline and the ink pipeline, the positive-negative pressure assembly provides the negative pressure to the ink tank, and closes the ink cartridge valve and opens the second valve, the ink pump is then closed, and after sensing that an ink level of the ink tank meets a standard, the heating assembly is activated to heat the ink in the ink tank and the printer head.

3. The ink circulation system of claim 1 , wherein when the ink circulation system is in a loop printing mode, the positive-negative pressure assembly is activated and the negative pressure is provided, the first valve is opened, and after sensing that an ink level of the ink tank meets a standard, the ink cartridge valve is closed and the second valve is opened, the ink pump is activated to fill the ink into the printer head, the heating assembly heats the ink in the ink tank and the printer head, and the printer head starts printing.

4. The ink circulation system of claim 1 , wherein when the ink circulation system is in an ink removal mode, after sensing that an ink level of the ink tank meets a standard, the ink cartridge valve and the first valve are closed and the second valve is opened, the positive-negative pressure assembly stops providing the negative pressure and opens the first valve, the ink pump is activated to fill the ink into the ink tank along the output pipeline and the ink pipeline, the positive-negative pressure assembly provides the positive pressure to the ink tank to squeeze the ink to be transmitted to the printer head.

5. The ink circulation system of claim 4 , further comprising a pressure sensor disposed on the first pipeline and used to detect a gas pressure value between the ink tank and the printer head.

6. The ink circulation system of claim 5 , wherein when the gas pressure value of the ink tank declines to a default value, the printer head is released from a clogged state.

7. The ink circulation system of claim 1 , wherein when the ink circulation system is in a bubble removal mode, after sensing that an ink level of the ink tank meets a standard, the ink cartridge valve and the first valve are closed and the second valve is opened, after the positive-negative pressure assembly stops providing the negative pressure, the first valve and the third valve are opened and the second valve is closed, the ink pump is activated to fill the ink into the ink tank along the output pipeline and the ink pipeline, and the positive-negative pressure assembly provides the positive pressure to the ink tank to squeeze the ink to pass through the printer head and the third valve.

8. The ink circulation system of claim 7 , further comprising a pressure sensor disposed on the first pipeline and used to detect a gas pressure value between the ink tank and the printer head.

9. The ink circulation system of claim 8 , wherein when the gas pressure value of the ink tank declines to a default value, the printer head is released from a clogged state.

10. The ink circulation system of claim 1 , wherein the ink tank further has a plurality of level sensors disposed on an outer surface of the ink tank and used to detect an ink level in the ink tank.

11. The ink circulation system of claim 1 , further comprising a weight sensor disposed at a bottom of the ink cartridge and used to detect an ink volume of the ink cartridge.

12. The ink circulation system of claim 1 , wherein the ink tank and the ink cartridge are made of metal materials.

13. The ink circulation system of claim 1 , wherein the output pipeline, the ink pipeline, the return pipeline, and the first pipeline are made of teflon.