CN103832080B - Assistant print cartridges, ink feeding system and inkjet-printing device - Google Patents

Abstract

The present invention proposes a secondary ink box for an inkjet printer, which includes an ink box cover and an ink box body. The first channel, the second channel and the third channel for realizing positive and negative pressure switching are arranged inside; the first channel hole, the second channel hole, the third channel hole and the fourth channel hole are also arranged on the boss part ; The first channel communicates with the first channel hole, the second channel communicates with the fourth channel hole, and the third channel connects the first channel hole and the third channel hole. The auxiliary ink box of the present invention forms a positive and negative pressure switching pipeline on the ink box cover, which can reduce pipeline connections, simplify maintenance, reduce the volume of the ink supply system, reduce the weight of the printing carriage, save costs, and improve printing quality.

Description

Secondary ink tank, ink supply system and inkjet printing device

technical field

The present invention relates to a secondary ink box, in particular to a highly integrated inkjet printer secondary ink box, an ink supply system using the secondary ink box, and an inkjet printing device including the ink supply system containing the secondary ink box.

Background technique

In recent years, due to the high printing speed and excellent image resolution of inkjet printing, and the combination of inkjet printing equipment and computers makes the design and layout of the final image more flexible, the popularity of inkjet printing technology The degree is getting higher and higher.

The inkjet printer nozzle trolley is equipped with a plurality of secondary ink tanks as shown in Figure 1, and the ink of various colors is supplied from each main ink tank to each secondary ink tank through the ink pipeline, and then each secondary ink tank supplies the ink to each nozzle; The ink cartridge includes an ink cartridge body 01 and an ink cartridge cover 02. In order to ensure the reliable supply of ink, a liquid level sensor 03 is installed on the secondary ink cartridge, and the liquid level sensor 03 is used to detect the amount of ink in the ink chamber, so as to automatically add ink when there is no ink. For ink, an ink outlet 04 is provided at the lower end of the ink box body 01 for supplying ink to the nozzle, and the ink box body 01 and the ink box cover 02 are connected by four corner screws 05 .

The installation height of the auxiliary ink tank on the existing inkjet printer is usually higher than the nozzle, and under the influence of gravity, the ink can naturally flow from the auxiliary ink tank to the nozzle. However, in order to achieve faster printing speed, the existing nozzle R&D and manufacturing technology level has been continuously improved, and the ignition frequency of nozzles for industrial inkjet printing is getting faster and faster. In order to ensure excellent printing quality at high printing speed, The printer is required to supply ink to the nozzle continuously, stably, quickly and in an appropriate amount according to the printing needs. The negative pressure ink supply system is often used in the prior art. If the negative pressure is too low, the ink will continue to flow downward under the action of gravity, and the excessive ink supply will cause ink dripping in the nozzle; if the negative pressure is too high, the ink in the nozzle will flow back, and the secondary The ink in the ink cartridge cannot flow to the nozzle in a timely and appropriate amount, resulting in no ink to be sprayed by the nozzle, and ink breakage occurs, which affects the printing quality.

As shown in Figure 2, the pipelines of the ink supply system in the prior art are complex, and the negative pressure system for monochrome printing mainly includes a secondary ink cartridge M1, four solenoid valves F1, F2, F3, F4, negative pressure sensor S1, negative pressure Cavity Q, negative pressure pump P1, positive pressure pump P2, pressure gauge S2, air pipe, air release valve f1, f2, nozzle H1 and control circuit, etc. The negative pressure value control circuit fed back by the negative pressure sensor S1 maintains the stability of the negative pressure in the pipeline by controlling the operation of the solenoid valves F1, F2 and the negative pressure pump P1. During the inkjet printing process, factors such as the loosening of the pipe joints caused by the back and forth vibration of the trolley, the aging of the negative pressure system pipeline, the air leakage of the gas pipe joint of the negative pressure system, the malfunction of the negative pressure pump and the failure of the air release valve will all cause The negative pressure is unstable, and the ink overflows from the nozzle, causing the nozzle to fail to print normally. The solenoid valve and negative pressure pump are frequently switched on and off, and the service life is shortened. For inkjet printers with more printing colors, the number of pipe joints in the negative pressure system is more, the air pipe is longer, and the detection is more difficult. There are 50 joints and 25 sections of pipelines in the six-color printing negative pressure system. Once the air leaks, there are many possible problems, and the difficulty of detection is further increased due to the invisibility of the air leak.

Contents of the invention

Aiming at the problems existing in the prior art, the object of the present invention is to provide a sub-ink box for an inkjet printing device with simple structure, convenient installation and high integration.

In order to achieve the above object, the present invention proposes a secondary ink box including an ink box cover and an ink box body, a liquid level sensor installation hole is arranged on the ink box cover, an ink tank for containing ink is arranged in the center of the ink box body, and the ink box body The upper end of the upper end is a sealing ring groove for accommodating the sealing ring. An ink inlet is arranged on the side wall of the ink box body. The ink box body and the ink box cover are connected by screws at four corners, and the sealing ring is arranged on the The space between the ink cartridge body and the ink cartridge cover is used to seal the ink cartridge body and the ink cartridge cover. It is characterized in that, the ink cartridge cover is provided with a boss portion for installing the first valve and the second valve, and the boss portion The first channel, the second channel and the third channel for realizing positive and negative pressure switching are arranged inside; the first channel hole, the second channel hole, the third channel hole and the fourth channel hole are also arranged on the boss part ; The first passage hole and the second passage hole respectively correspond to the air inlet and the air outlet of the first valve, and the third passage hole and the fourth passage hole correspond to the air inlet and the air outlet of the second valve respectively. The air outlet, the first channel communicates with the first channel hole, the second channel communicates with the fourth channel hole, and the third channel connects the first channel hole with the third channel hole .

In the above sub-ink cartridge, the first passage is connected to the negative pressure pump through the first joint and the air pipe, the second passage is connected to the positive pressure pump through the second joint and the air pipe, and the outlet of the third passage is connected to the third joint seal.

In the above sub-ink box, the lower end of the ink box body is provided with a fourth channel, a fifth channel and a sixth channel, the fourth channel is connected to the fifth channel through a third valve, and the fifth channel is connected to the first channel. The six channels are connected, the outlet of the sixth channel is connected to the sixth joint, and the sixth joint supplies ink to the nozzle through the ink tube.

In the above-mentioned auxiliary ink cartridge, an air inlet is also arranged on the ink cartridge cover, and a fourth joint is installed on the air inlet, and the fourth joint is connected with the inlet end of a one-way valve through a gas pipe, and the one-way The outlet end of the valve is connected to the first joint through the air pipe. When the secondary ink tank overflows, the one-way valve is in a cut-off state, and the ink cannot flow from the inlet end of the one-way valve to the outlet end, thereby preventing the first valve from Damaged by ink flooding.

In the above-mentioned auxiliary ink cartridge, the first valve, the second valve, and the third valve are all solenoid valves, wherein the first valve and the second valve are two-position three-way solenoid valves, and the third valve is a two-position three-way solenoid valve. Two-way solenoid valve.

The purpose of the present invention is also to provide an ink supply system comprising a sub-ink box, wherein the sub-ink box includes an ink box cover and an ink box body, and the ink box cover is provided with protrusions for installing the first valve and the second valve. The platform part, the inside of the boss part is provided with the first channel, the second channel and the third channel for switching between positive and negative pressure; the boss part is also provided with the first channel hole, the second channel hole and the The third channel hole and the fourth channel hole; the first channel communicates with the first channel hole, and the first channel hole and the second channel hole respectively correspond to the air inlet and the air outlet of the first valve, The third passage hole and the fourth passage hole respectively correspond to the air inlet and the air outlet of the second valve, the second passage communicates with the fourth passage hole, and the third passage connects the first the channel hole and the third channel hole.

In the above ink supply system, the lower end of the ink cartridge body is provided with a fourth channel, a fifth channel and a sixth channel, the fourth channel is connected to the fifth channel through a third valve, and the fifth channel is connected to the The sixth channel is connected, the outlet of the sixth channel is connected to the sixth joint, and the sixth joint supplies ink to the nozzle through the ink tube.

In the above ink supply system, the ink cartridge cover is also provided with an air intake hole, and a fourth joint is installed on the air intake hole, and the fourth joint is connected to the inlet end of a one-way valve through an air pipe, and the one-way valve The outlet end of the valve is connected to the first joint through a gas pipe.

Another object of the present invention is to propose an inkjet printing device comprising a sub-ink box, including a printing carriage, an ink supply system is arranged on the printing trolley, it is characterized in that the sub-ink box includes an ink box cover and an ink box body, so The ink cartridge cover is provided with a boss portion for installing the first valve and the second valve, and the inside of the boss portion is provided with a first channel, a second channel and a third channel for switching between positive and negative pressure; The boss portion is also provided with a first channel hole, a second channel hole, a third channel hole, and a fourth channel hole; the first channel hole and the second channel hole correspond to the air inlet and the first valve respectively. The air outlet, the third passage hole and the fourth passage hole respectively correspond to the air inlet and the air outlet of the second valve, the first passage communicates with the first passage hole, and the second passage communicates with the second passage. The fourth passage hole communicates with each other, and the third passage connects the first passage hole and the third passage hole.

In the above inkjet printing device, the lower end of the ink cartridge body is provided with a fourth passage, a fifth passage and a sixth passage, the fourth passage is connected to the fifth passage through a third valve, and the fifth passage is connected to the fifth passage. The sixth channel is connected, the outlet of the sixth channel is connected to the sixth joint, and the sixth joint supplies ink to the nozzle through the ink tube.

In the above-mentioned inkjet printing device, the ink cartridge cover is also provided with an air intake hole, and a fourth joint is installed on the air intake hole, and the fourth joint is connected to the inlet end of a one-way valve through a gas pipe, and the The outlet end of the one-way valve is connected with the first connector through a gas pipe.

Description of drawings

Fig. 1 is the perspective view of secondary ink cartridge in the prior art;

Fig. 2 is the schematic diagram of the ink supply system in the prior art that adopts the sub-ink box described in Fig. 1;

Figure 3 is a perspective view of the sub-ink cartridge in one embodiment of the present invention;

Fig. 4 is the front view of the secondary ink tank in one embodiment of the present invention;

Fig. 5 is the back view of sub-ink box in one embodiment of the present invention;

Figure 6 is a three-dimensional exploded view of the sub-ink cartridge in one embodiment of the present invention;

Figure 7 is a perspective view of the ink cartridge cover shown in serial number 1 in Figure 3;

Figure 8 is a side view of the ink cartridge cover shown in serial number 1 in Figure 3;

Fig. 9 is a B-B sectional view of Fig. 8;

Fig. 10 is a C-C sectional view of Fig. 8;

Figure 11 is a D-D sectional view of Figure 10;

Fig. 12 is the front view of the ink cartridge body shown in serial number 2 in Fig. 3;

Fig. 13 is A-A sectional view of Fig. 12;

Figure 14 is a schematic diagram of an ink supply system in one embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 3 to 6, the secondary ink box in one embodiment of the present invention includes an ink cartridge cover 1 and an ink cartridge body 2, the ink cartridge cover 1 includes a horizontal portion 1a and a boss portion 1b, and the first ink cartridge is installed on the boss portion 1b. Valve 3 and second valve 4, the first valve 3 is a negative pressure valve, the second valve 4 is a positive pressure valve, and a liquid level sensor 6 is installed on the horizontal part 1a of the ink cartridge cover 1. The ink cartridge cover 1 is connected with the ink cartridge body 2 through threaded holes and screws arranged at four corners. In order to avoid air leakage between the ink cartridge cover 1 and the ink cartridge body 2, a seal ring 9 is also arranged between the ink cartridge cover 1 and the ink cartridge body 2, and the seal ring 9 is arranged in the seal ring groove 23 on the upper end of the ink cartridge body 2 . At the lower end of the cartridge body 2, a third valve 5 is installed. The first valve 3, the second valve 4 and the third valve 5 in this embodiment are all solenoid valves, wherein the first valve 3 and the second valve 4 are two-position three-way valves, and the third valve 5 is two-position two-way valves valve. An air inlet 16 is also provided on the horizontal portion 1 a of the ink cartridge cover 1 . A fourth connector 84 is installed on the inlet hole 16 , and a one-way valve 7 is connected in series between the fourth connector 84 and the first valve 3 . The one-way valve 7 is used to slow down or stop the speed of ink flowing from the sub-tank to the first valve 3 when the sub-tank overflows, so as to avoid damage to the first valve 3 due to ink flooding. A fifth connector 85 is installed at the upper middle part of the side of the ink cartridge body 2, which is an ink inlet connector, and the fifth connector 85 is connected with the main ink cartridge arranged at the bottom of the inkjet printing through the ink tube.

Figure 7 is a perspective view of the ink cartridge cover in one embodiment of the present invention. In the ink cartridge cover 1 in one embodiment of the present invention, the first mounting hole 11a of the first valve 3, the second The installation hole 11b and the first passage hole 13a and the second passage hole 13b of the first valve 3, the third installation hole 12a and the fourth installation hole 12b of the second valve 4 and the third passage hole 14a and the second passage hole 14a of the second valve 4 Four-channel hole 14b. The first valve 3 is fixed on the boss portion 1b of the ink cartridge cover 1 by screwing two screws into the first mounting hole 11a and the second mounting hole 11b respectively, and the first channel hole 13a and the second channel hole 13b are respectively connected to the The air inlet of the first valve 3 and the air outlet of the first valve 3; the second valve 4 is fixed on the boss portion 1b of the ink cartridge cover 1 by screwing two screws into the third mounting hole 12a and the fourth mounting hole 12b respectively Above, the third passage hole 14a and the fourth passage hole 14b are respectively connected to the air inlet of the second valve 4 and the air outlet of the second valve 4 . A sensor mounting hole 15 and an air inlet 16 are set on the horizontal portion 1a of the ink cartridge cover 1, the sensor mounting hole 15 is used to install the liquid level sensor 6, and the liquid level sensor 6 is used to detect the amount of ink in the secondary ink box so that Automatically add ink when the secondary ink tank is short of ink, and automatically stop ink supply when the secondary ink tank is short of ink. In one embodiment of the present invention, the liquid level sensor 6 is a secondary liquid level float sensor. An air inlet joint 71 is installed on the air inlet 16 .

As shown in Figure 4 and Figure 8, a first channel 17a and a second channel 17b are provided on one side of the boss portion 1b of the ink cartridge cover 1, the first channel 17a is a negative pressure air inlet, and the outlet of the first channel 17a A first connector 81 is installed, and the first connector 81 is connected with the negative pressure pump through the air pipe; Connect to positive pressure pump. A third channel 18 is provided on the other side of the boss portion 1 b of the ink cartridge cover 1 , and a third joint 83 is installed in the third channel 18 . The third joint 83 is used to close the outlet of the third channel 18 .

FIG. 9 is a cross-sectional view along line B-B of FIG. 8 , where the second channel 17b vertically connects with the fourth channel hole 14b.

Fig. 10 is a C-C sectional view of Fig. 8, the first channel 17a is vertically connected with the third channel 18.

11 is a D-D sectional view of FIG. 10 , the third channel 18 communicates with the first channel hole 13a and the third channel hole 14a, and the third channel 18 vertically intersects the first channel hole 13a and the third channel hole 14a.

As shown in Figures 12 to 13, an ink tank 22 for accommodating ink is arranged at the center of the ink cartridge body 2 in one embodiment of the present invention, and a sealing ring groove for accommodating the sealing ring 9 is arranged at the upper end of the ink cartridge body 2 23. An ink inlet 24 is arranged on the middle and upper part of one side of the ink cartridge body 2, an ink inlet joint 85 is installed on the ink inlet 24, and the fourth channel 21a, the fifth channel 21b and the sixth channel are arranged on the lower part of the ink cartridge body 2 21c. The fourth passage 21a communicates with the ink tank 22, the fifth passage 21b communicates with the sixth passage 21c, a third valve 5 is connected between the fourth passage 21a and the fifth passage 21b, and the entrance of the fourth passage 21a and the third valve 5 The outlet of the third valve 5 is connected to the fifth channel 21b, the third valve 5 is a two-position two-way solenoid valve, the outlet of the sixth channel 21c is connected to the sixth joint 86, and the sixth joint 86 is connected to the nozzle through the ink tube. For ink supply, in order to ensure the purity of the ink supplied to the nozzle, a filter can also be arranged between the sixth joint 86 and the ink inlet of the nozzle. The third valve 5 has two states of on and off. When the third valve 5 is on, the fourth channel 21a and the fifth channel 21b are connected, ink flows from the sub-ink box to the nozzle, and the inkjet printer performs inkjet printing. When the third valve 5 is disconnected, the fourth channel 21a and the fifth channel 21b are blocked. This state is used to cut off the ink supply from the sub-ink box to the nozzle when the inkjet printer stops working. In the present invention, a fourth valve that is fully consistent with the third valve 5 in action and function can be installed on the ink cartridge body 2 for accessing the cleaning liquid and a corresponding installation channel for the fourth valve is provided.

The sub-ink cartridge of the present invention has the following advantages: 1. Forming a positive and negative pressure switching pipeline on the ink cartridge cover can reduce pipeline connections, simplify maintenance, reduce the volume of the ink supply system, reduce the weight of the printing carriage, save costs, and improve printing quality. 2. Form an on-off channel on the ink cartridge body and install a two-way valve to automatically turn on and off the ink path between the sub-ink box and the nozzle, realize the full automation of the entire printing ink supply system, and reduce the components at the outlet of the sub-ink box Quantity, cost savings, and simplification of the entire ink supply system. 3. The ink supply pipeline is a full-through pipeline, which is easy to clean and prevents the nozzle holes from being clogged due to the residual metal shavings when the dead-end pipeline is formed by machining.

Fig. 14 is the ink supply system that adopts the sub-ink box of the present invention, the ink supply system of the present invention includes a sub-ink box M2, the first valve F1 and the second valve F2 are installed on the ink box cover of the sub-ink box M2, the first valve F1 is directly connected to The negative pressure pump P1 is connected to the negative pressure pump through a gas cylinder Q, and the function of the gas cylinder Q is to make the negative pressure in the sub-ink M2 more stable. In order to control the degree of negative pressure of the auxiliary ink tank M2, a first flow limiting valve f1 is connected in series between the first valve F1 and the negative pressure pump P1. A fourth valve F4 and a third flow limiting valve f3 connected to the fourth valve F4 are also arranged on the negative pressure channel of the auxiliary ink tank M2. The second valve F2 is directly connected to the positive pressure pump P2. In order to adjust the positive pressure of the auxiliary ink tank M2, a second flow limiting valve f2 is connected in series between the second valve F2 and the positive pressure pump P2. The ink cartridge cover of the auxiliary ink cartridge M2 is also built with an internal channel for switching between positive and negative pressure. A negative pressure sensor S1 and/or a pressure gauge S2 for detecting pipeline air pressure can be connected in series on the pipeline at the outlet of the gas cylinder Q. A liquid level sensor S3 is installed on the secondary ink tank M2 to detect the liquid level of the ink in the secondary ink tank M2 so as to add ink in time when the ink is short of ink, and stop the ink supply when the ink is full. Install the third valve F3 on the ink box body of the sub-ink box M2, the ink in the sub-ink box M2 flows to the nozzle through the third valve F3, in order to ensure that the ink flowing into the nozzle H1 does not have impurities, between the sub-ink M2 and the third valve F3 A filter can also be set. During inkjet printing, the first valve F1 is in the open state, the second valve F2 is in the closed state, the third valve F3 is in the open state, and the fourth valve F4 is in the closed state. At this time, the negative pressure pump P1 is in the working state, and the positive pressure pump P2 is in the non-working state, the air pressure in the sub-ink M2 is negative pressure, and the ink is continuously and stably supplied to the nozzle H1 through the sub-ink M2 according to the printing demand. When the negative pressure sensor S1 detects that the negative pressure in the auxiliary ink tank M2 is too high, the fourth valve F4 is opened to enter a part of the air to reduce the negative pressure in the auxiliary ink tank M2; when the negative pressure in the auxiliary ink tank M2 is at a normal level, the fourth valve F4 F4 closes. When the nozzle hole of nozzle H1 is blocked and needs to be dredged, the first valve F1 is closed, the second valve F2 is open, the third valve F3 is open, and the fourth valve F4 is closed. At this time, the negative pressure pump P1 is In the non-working state, the positive pressure pump P2 is in the working state, the air pressure in the sub-ink M2 is positive pressure, and the ink in the sub-ink M2 impacts the nozzle holes under the positive pressure to clear the blocked nozzle holes.

The ink supply system in the multi-color inkjet printing device may include multiple secondary ink tanks M2, and the multiple secondary ink tanks M2 are connected in parallel to the negative pressure pump P1 and the positive pressure pump P2 respectively. The present invention can also control the pressure in each sub-ink M2 separately, and the pressure in each sub-ink M2 is an independent ink supply system, as shown in FIG. 14 .

The sub-ink box of the present invention and the ink supply system composed of the sub-ink box of the present invention can be used in any ink-jet printer using negative pressure ink supply to realize continuous and stable ink supply to the nozzle.

It should be pointed out that any modification made according to the specific embodiments of the present invention shall not deviate from the spirit of the present invention and the scope described in the claims.

Claims (10)

1. A secondary ink box, comprising an ink box cover and an ink box body, a liquid level sensor installation hole is set on the said ink box cover, an ink groove for containing ink is arranged at the center of the said ink box body, and the upper end of the said ink box body is used for A sealing ring groove for accommodating the sealing ring, an ink inlet is arranged on the side wall of the ink box body, the ink box body and the ink box cover are connected by screws at four corners, and the sealing ring is arranged on the ink box body and the ink box cover The ink cartridge cover is used to seal the ink cartridge body and the ink cartridge cover. It is characterized in that, the ink cartridge cover is provided with a boss for installing the first valve and the second valve, and the inside of the boss is A first channel, a second channel and a third channel are provided for switching between positive and negative pressure; the boss part is also provided with a first channel hole, a second channel hole, a third channel hole, and a fourth channel hole; The first passage hole and the second passage hole respectively correspond to the air inlet and the air outlet of the first valve, and the third passage hole and the fourth passage hole respectively correspond to the air inlet and the outlet of the second valve. An air port, the first channel communicates with the first channel hole, the second channel communicates with the fourth channel hole, and the third channel connects the first channel hole and the third channel hole. 2. The auxiliary ink cartridge according to claim 1, wherein the first passage is connected with the negative pressure pump through the first joint and the air pipe, and the second passage is connected with the positive pressure pump through the second joint and the air pipe, The outlet of the third channel is sealed by a third joint. 3. The auxiliary ink box according to claim 1, wherein the lower end of the ink box body is provided with a fourth passage, a fifth passage and a sixth passage, and the fourth passage is connected with the fifth passage through the third valve. The channels are connected, the fifth channel communicates with the sixth channel, and the outlet of the sixth channel is connected to the sixth joint. 4. secondary ink cartridge as claimed in claim 3, is characterized in that, described first valve, second valve and the 3rd valve are electromagnetic valves. 5. secondary ink box as claimed in claim 2, is characterized in that, described ink cartridge cover is also provided with an air inlet hole, and a 4th joint is installed on the described air inlet hole, and described 4th joint connects with a single through trachea. The inlet port of the one-way valve is connected to the inlet port of the one-way valve, and the outlet port of the one-way valve is connected to the first joint through the air pipe. 6. An ink supply system comprising a sub-ink box, characterized in that, the sub-ink box includes an ink cartridge cover and a ink box body, the ink box cover is provided with a boss portion for installing the first valve and the second valve, the described The inside of the boss part is provided with a first channel, a second channel and a third channel for switching between positive and negative pressure; the boss part is also provided with a first channel hole, a second channel hole and a third channel hole, The fourth passage hole; the first passage hole and the second passage hole respectively correspond to the air inlet and the air outlet of the first valve, and the third passage hole and the fourth passage hole correspond to the second valve respectively. an air inlet and an air outlet, the first channel communicates with the first channel hole, the second channel communicates with the fourth channel hole, and the third channel connects the first channel hole with the third channel hole. 7. ink supply system as claimed in claim 6, is characterized in that, the lower end of described ink box body is provided with the 4th channel, the 5th channel and the 6th channel, and described 4th channel is connected with described 5th channel through the 3rd valve. The channels are connected, the fifth channel communicates with the sixth channel, and the outlet of the sixth channel is connected to the sixth joint. 8. ink supply system as claimed in claim 6, is characterized in that, described ink cartridge cover is also provided with an air intake hole, and a fourth joint is installed on the described air intake hole, and described fourth joint connects with a trachea through air pipe. The inlet end of the one-way valve is connected, and the outlet end of the one-way valve is connected with the first connector through the air pipe. 9. An inkjet printing device comprising a sub-ink box, comprising a printing carriage, an ink supply system is set on the printing trolley, it is characterized in that, the sub-ink box includes an ink box cover and an ink box body, and the ink box cover is provided with a For the boss part where the first valve and the second valve are installed, the inside of the boss part is provided with the first passage, the second passage and the third passage for realizing positive and negative pressure switching; the boss part is also provided with There are a first channel hole, a second channel hole, a third channel hole, and a fourth channel hole; the first channel hole and the second channel hole respectively correspond to the air inlet and the air outlet of the first valve, and the first channel hole corresponds to the air inlet and the air outlet of the first valve. The three channel holes and the fourth channel hole respectively correspond to the air inlet and the air outlet of the second valve, the first channel communicates with the first channel hole, and the second channel communicates with the fourth channel hole , the third channel connects the first channel hole and the third channel hole. 10. inkjet printing device as claimed in claim 9, is characterized in that, the lower end of described ink box body is provided with the 4th passage, the 5th passage and the 6th passage, and described 4th passage passes through the 3rd valve and described the 6th passage. Five channels are connected, the fifth channel communicates with the sixth channel, and the outlet of the sixth channel is connected to the sixth joint.