Inkjet printer viscosity detection device

Abstract

The present invention provides a viscosity detection device for an inkjet printer. The viscosity detection device for an inkjet printer does not have any moving parts such as valves, and is simply composed of firmware. It uses the siphon principle to automatically and periodically sample from the ink system and fill the viscosity detection chamber without any interference with the flow and pressure of the ink system, thereby effectively improving the stability of the inkjet printer operation.

Description

Technical Field

[0001] The present invention relates to the field of inkjet printing technology, and in particular to a viscosity detection device for an inkjet printer. Background Art

[0002] Industrial inkjet printers operate by utilizing the principle of electrostatic induction, using the CPU to control the voltage on the charging electrode, thereby indirectly controlling the charge of the ink dots ejected from the nozzle at high speed. This results in ink dots with different charges being subjected to different electric forces when passing through the high-voltage electrostatic field, resulting in different deflections and landing at different locations on the surface of the object, forming the printed content. The vast majority of ink dots with zero charge experience no deflection and are ejected directly at high speed into the negative pressure recovery pipe at the end of the printhead. There, they mix with the high-speed return air and enter the ink system for recycling. The large amount of air recovered along with the uncharged ink dots is then discharged from the printer through the exhaust pipe.

[0003] Since the ink of the inkjet printer needs to dry quickly after being printed on the surface of the object, most inks use highly volatile solvents. The waste gas discharged after recycling will carry a large amount of solvent volatiles. As the use time continues, the viscosity of the ink in the inkjet printer will gradually increase, affecting the formation of ink dots. In order to ensure the continuous and stable operation of the machine, the viscosity of the ink in the inkjet printer must be detected in real time to replenish the volatilized solvent in time. To achieve real-time detection of the ink viscosity of the inkjet printer, please refer to Figure 1 , which is a viscosity detection device for inkjet printers used in the prior art, such as Figure 1As shown, the device consists of a viscosity detection chamber 2', a liquid level sensor 5' (including a high-level switch 5-1' and a low-level switch 5-2'), a sampling port 0-1', a sampling valve 0-2', a throttling drain pipe 2-4', an overflow balancing port 2-3', and a mixing tank 4'. The device is mounted above the mixing tank 4'. When the printer is running, ink in the mixing tank 4' is pumped and pressurized by an ink pump before being supplied to the nozzle. Under the control of the CPU, ink is printed onto the surface of the printed material. Any ink not involved in printing flows back into the mixing tank 4', and this cycle repeats. The mixing tank acts as a circulation pool for the printer's ink system. The operating mechanism of the device is to connect the sampling valve 0-2' to the sampling interface 0-1' of the ink system of the inkjet printer, and fill the viscosity detection chamber 2' with the ink to be tested by controlling the opening of the sampling valve 0-2'. Then, the sampling valve 0-2' is closed, and the ink filled in the viscosity detection chamber 2' will be gradually discharged from the throttling drain pipe 2-4' at the bottom of the cavity into the mixing cylinder 4', thereby causing the liquid level position of the viscosity detection chamber 2' to continue to decrease. By monitoring the changes in the liquid level switch signal of the liquid level sensor 5' installed in the viscosity detection chamber 2', the viscosity changes of the running ink in the ink system of the inkjet printer are indirectly judged, and the CPU uses this as the basis for adjusting the viscosity. In order to ensure the air pressure balance during operation, an air pressure balance port 4-1' connected to the external atmosphere is opened on the top of the mixing cylinder 4'.

[0004] For ease of understanding, the above mechanism is further described: each time the viscosity of the ink is checked, the sampling valve 0-2' is first opened to fill the viscosity detection chamber 2' with the ink to be tested, and then the sampling valve 0-2' is closed. The ink to be tested in the viscosity detection chamber 2' will be gradually discharged into the mixing cylinder 4' through the throttling drain pipe 2-4', causing the liquid level in the detection chamber 2' to continue to decrease. When the liquid level is lower than the high liquid level switch 5-1', the state of the high liquid level switch 5-1' will change from on to off, and the CPU will record this point as t1. As the liquid level in the detection chamber 2' continues to decrease, when the liquid level of the ink to be tested is lower than the low liquid level switch 5-2', the state of the low liquid level switch 5-2' will change from on to off, and the CPU will record this point as t2. The larger the viscosity value of the ink to be tested, the longer the time ΔT (ΔT = t2 – Therefore, by repeatedly controlling the opening and closing of the sampling valve 0-2' to fill the viscosity monitoring chamber 2' with the ink to be tested and then empty it, and monitoring the time period ΔT of each change in the liquid level switch state of the liquid level sensor during the emptying period, the viscosity change of the ink of the inkjet printer can be monitored in real time. When the ink viscosity exceeds the standard, an alarm is given or solvent is added in time to adjust the ink in the mixing tank to the set target viscosity state, so as to achieve the best working condition of the inkjet printer.

[0005] However, the viscosity detection device of the inkjet printer uses the opening and closing of the sampling valve 0-2' to control whether the viscosity chamber is filled or not. When the valve is switched on and off, the flow and pressure of the entire ink system will fluctuate. The shape and phase of the ink dots will also drift periodically with the opening and closing of the valve, thereby affecting the accuracy of the ink dot charging. In severe cases, typing will be deformed or blurred.

[0006] In view of the shortcomings of the viscosity detection device of the inkjet printer in the prior art, those skilled in the art have been looking for solutions. Summary of the Invention

[0007] The present invention aims to provide a viscosity testing device for inkjet printers. This device continuously and uninterruptedly injects the ink to be tested into a first chamber. When the ink level rises to a certain level, a siphon effect is triggered. The ink in the chamber is then rapidly transferred (injected) into the viscosity testing chamber. Simultaneously, the first chamber's liquid level rapidly drops, ending the siphoning process. Continued injection causes the first chamber's liquid level to rise again, triggering the next round of siphoning. This device aims to replace the valve opening and closing mechanism used in existing viscosity testing technologies with the aforementioned mechanism, addressing the flow and pressure fluctuations caused by valve-controlled sampling in existing ink viscosity testing solutions, which in turn lead to poor print quality and reduced printing stability.

[0008] In order to solve the above technical problems, the present invention provides a viscosity detection device for an inkjet printer, which includes: a first chamber, a viscosity detection chamber, a mixing cylinder, a throttling drain pipe, a siphon tube and a liquid level sensor; wherein the siphon tube has a first port and a second port, the first port of the siphon tube is close to the bottom of the inner cavity of the first chamber, the second port of the siphon tube passes through the body wall of the first chamber and is connected to the viscosity detection chamber, and the second port is lower than the first port; a sampling interface connected to the ink system is provided on the first chamber, the bottom surface of the first chamber is higher than the bottom surface of the viscosity detection chamber, the volume of the first chamber is larger than the volume of the viscosity detection chamber, and a first overflow balancing port connected to the top of the viscosity detection chamber is provided on the top of the first chamber; the throttling drain pipe is provided at the bottom of the viscosity detection chamber, and the other end of the throttling drain pipe is connected to the top of the mixing cylinder; a second overflow balancing port connected to the top of the mixing cylinder is provided on the side wall of the viscosity detection chamber.

[0009] Optionally, in the viscosity detection device for the inkjet printer, the siphon tube is an inverted U-shaped tube, and the highest position of the inverted U-shaped tube is lower than the first overflow balance port.

[0010] Optionally, the inkjet printer viscosity detection device further includes: a flow limiting damping tube serially connected to the pipeline connected to the sampling interface.

[0011] Optionally, in the inkjet printer viscosity detection device, the liquid level sensor includes: a high liquid level switch and a low liquid level switch.

[0012] Optionally, in the viscosity detection device of the inkjet printer, the sensing liquid level of the high liquid level switch is lower than the position of the second overflow balancing port.

[0013] Optionally, the inkjet printer viscosity detection device further includes an air pressure balance port opened at the top of the mixing cylinder and connecting the mixing cylinder to the atmosphere.

[0014] The present invention provides a viscosity detection device for an inkjet printer. The viscosity detection device for an inkjet printer does not have any moving parts such as valves, but is simply composed of firmware. It uses the siphon principle to automatically and periodically extract samples from the ink system and fill the viscosity detection chamber without any interference with the flow and pressure of the ink system, thereby effectively improving the stability of the inkjet printer operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0016] Figure 1 It is a structural diagram of a viscosity detection device for an inkjet printer in the prior art;

[0017] Figure 2 2 is a schematic structural diagram of a viscosity detection device for an inkjet printer according to an embodiment of the present invention;

[0018] Figure 1 Middle: 2'-viscosity detection chamber; 2-3'-overflow balance port; 2-4'-throttling drain pipe; 0-1'-sampling interface; 0-2'-sampling valve; 5'-liquid level sensor; 5-1'-high liquid level switch; 5-2'-low liquid level switch; 2-3-second overflow balance port; 4'-mixing cylinder; 4-1'-air pressure balance port;

[0019] Figure 2 Middle: 1-first chamber; 1-2-first overflow balance port; 2-viscosity detection chamber; 2-3-second overflow balance port; 2-4-throttling drain pipe; 3-siphon tube, 3-1-first port of siphon tube; 3-2-second port of siphon tube; 3-3-top of siphon tube; 0-1-sampling interface; 4-mixing cylinder; 4-1-air pressure balance port; 5-liquid level sensor; 5-1-high liquid level switch; 5-2-low liquid level switch. DETAILED DESCRIPTION

[0020] The viscosity detection device for inkjet printers proposed in the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the accompanying drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0021] Please refer to Figure 2 , which is a schematic diagram of the structure of the viscosity detection device of the inkjet printer of the present invention. Figure 2 As shown,

[0022] The viscosity detection device of the inkjet printer includes a first chamber 1, a viscosity detection chamber 2, a siphon tube 3, a mixing cylinder 4 and a liquid level sensor 5; the first chamber 1, the viscosity detection chamber 2 and the top of the mixing cylinder 4 are freely connected, and the first chamber 1 and the viscosity detection chamber 2 are installed on the top of the mixing cylinder 4; the siphon tube 3 connects the first chamber 1 with the viscosity detection chamber 2, the first port 3-1 of the siphon tube 3 is close to the bottom of the inner cavity of the first chamber 1, and the second port 3-2 passes through the body wall of the first chamber 1 and is connected to the viscosity detection chamber 2, and the second port 3-2 of the siphon tube 3 is lower than the first port 3-1, and the top 3-3 of the siphon tube is higher than the first port 3-1; the bottom surface of the first chamber 1 is higher than the viscosity detection chamber 2. The volume of the first chamber 1 on the bottom surface of the viscosity detection chamber 2 is larger than that of the viscosity detection chamber 2; the first chamber is provided with a sampling interface 0-1 connected to the ink circuit; the top of the first chamber 1 is provided with a first overflow balance port 1-2 connected to the top of the viscosity detection chamber 2; the bottom of the viscosity detection chamber 2 is provided with a throttling drain pipe 2-4, the other end of which opens at the top of the mixing cylinder 4, and the liquid in the viscosity detection chamber 2 can freely fall into the mixing cylinder 4 through the throttling drain pipe 2-4; the side wall of the viscosity detection chamber 2 is provided with a second overflow balance port 2-3 connected to the top of the mixing cylinder 4, and a liquid level sensor 5 is installed on the viscosity detection chamber 2. Among them, the liquid level sensor 5 includes a high liquid level switch 5-1 and a low liquid level switch 5-2, and the sensing liquid level of the high liquid level switch 5-1 is lower than that of the second overflow balance port 2-3.

[0023] In this embodiment, the top of the mixing cylinder is also provided with an air pressure balance port 4-1 connected to the atmosphere; since the first chamber, the viscosity detection chamber and the mixing cylinder in the viscosity detection device of the inkjet printer are interconnected, and the mixing cylinder is connected to the atmosphere, the air pressure in the three is consistent with the atmospheric pressure.

[0024] Preferably, the siphon tube 3 is an inverted U-shaped tube, which passes through the body wall of the first chamber 1 and is connected with the second chamber 2; wherein, the highest position of the inverted U-shaped tube is lower than the first overflow balance port 1-2, so that the liquid level in the first chamber 1 gradually rises until it submerges the top 3-3 of the siphon tube 3 (i.e., the highest position of the siphon tube 3), triggering the siphon effect, and a large amount of ink to be tested in the first chamber 1 quickly flows into the viscosity detection chamber 2 through the siphon tube. Since the volume of the first chamber 1 is larger than the volume of the viscosity detection chamber 2, the amount of ink to be tested injected by the siphon effect is sufficient to completely cover and trigger the high-level switch 5-1 of the liquid level sensor 5 to turn on. As the ink to be tested injected by the siphon effect slowly flows into the mixing cylinder 4 through the throttling drain pipe 2-4, the liquid level switch signal of the liquid level sensor 5 will cause alternating changes. By monitoring the liquid level sensor switch signal at this time, the viscosity change of the ink to be tested can be indirectly detected. Here, the specific structure of the siphon tube 3 includes but is not limited to an inverted U-shaped tube, and any form that can induce a siphon effect is acceptable.

[0025] For details, please refer to Figure 2 , Figure 2 This sensor specifically refers to a liquid level sensor made of three conductive metal rods (probes) of different lengths. Because ink is conductive, the resistance between the two long and short probes and the longest probe can be measured to determine whether the ink level covers the probes. The viscosity value can be determined by simply measuring the time difference between the high-level probe and the low-level probe. The liquid level sensor 5 of the present invention is not limited to sensors that provide high and low level signals. It can also be a float switch with two sensing positions, or other forms.

[0026] Preferably, the viscosity detection device of the inkjet printer further includes an evaluation device electrically connected to the liquid level sensor 5 to collect statistics on the liquid level change signal in the viscosity detection chamber 2 sensed by the liquid level sensor 5. The evaluation device indirectly determines the viscosity of the liquid in the viscosity detection chamber 2 based on the time difference between when the liquid level in the viscosity detection chamber 2 flows empty from the high-level probe (corresponding to the high liquid level switch) to when the low-level probe (corresponding to the low liquid level switch) flows empty. In this embodiment, the evaluation device is preferably a CPU.

[0027] In order to better understand the viscosity detection device of the inkjet printer of the present invention, the following Figure 2 Describe in detail the working status of the viscosity detection device of the inkjet printer during actual application.

[0028] Please refer to Figure 2The specific working process is as follows: the ink in the ink system of the inkjet printer continuously flows into the first chamber 1 at a high position through the sampling interface 0-1, and gradually raises the liquid level position of the first chamber 1. If there is too much ink, it will flow out through the first overflow balance port 1-2 and fall into the mixing cylinder 4 under the action of gravity. When the liquid level position of the first chamber 1 exceeds the top 3-3 of the siphon tube 3, a siphon phenomenon will be triggered. At this time: the ink in the first chamber 1 will quickly flow into the viscosity detection chamber 2 through the siphon tube 3, and at the same time, the liquid level position of the first chamber 1 will quickly drop to the first port 3-1 of the siphon tube 3, and air will enter the siphon tube 3 and interrupt the siphon. As the sampling interface 0-1 continues to slowly replenish new ink to the first chamber 1, the liquid level of the first chamber 1 will gradually rise again until the next siphon is triggered, and the viscosity detection chamber 2 will be quickly filled again, and the cycle will repeat.

[0029] When the ink in the first chamber 1 rapidly enters the viscosity detection chamber 2 through the siphon tube 3, the liquid level in the viscosity detection chamber 2 rapidly rises to the second overflow balancing port 2-3. Excess ink flows out through the second overflow balancing port 2-3 and freely falls into the mixing tank 4. The ink to be tested in the viscosity detection chamber 2 continues to flow into the mixing tank 4 through the throttling drain pipe 2-4. At the same time, the liquid level in the viscosity detection chamber 2 gradually decreases. When the ink level to be tested falls below the high liquid level switch 5-1, the CPU records this moment as t1. When the ink level to be tested falls below the low liquid level switch 5-2, the CPU records this moment as t2. The greater the viscosity of the ink to be tested, the longer the time ΔT (ΔT = t2 – t1) for the ink level to change from the high liquid level switch to the low liquid level switch, and vice versa. After the ink to be tested in the viscosity detection chamber 2 is emptied, it waits for the next siphon.

[0030] Therefore, through the repetition of the siphon phenomenon, the running ink can be continuously and intermittently injected from the first chamber 1 into the viscosity detection chamber 2, and the time period ΔT of the change in the liquid level switch state of the liquid level sensor 5 is monitored, so as to monitor the change in the viscosity of the inkjet printer ink in real time.

[0031] Preferably, in order to ensure that the period of ink filling the first chamber to generate the siphon phenomenon is longer than the time for the viscosity detection chamber to be completely emptied, it is necessary to connect a suitable flow limiting damping tube 0-3 (such as Figure 2 as shown), to effectively limit the flow rate of the sampled liquid.

[0032] In summary, the entire ink sampling process does not involve any moving parts such as valves. Ink sampling is continuous and automatic. Based on the siphon principle, samples are automatically and periodically taken from the ink system and filled into the viscosity detection chamber. Therefore, there is no interference with the flow and pressure of the ink system, and the stability of the inkjet coding equipment operation is greatly improved.

[0033] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A viscosity detection device for an inkjet printer, characterized in that: include: A first chamber, a viscosity detection chamber, a mixing cylinder, a throttling drain pipe, a siphon tube and a liquid level sensor; wherein, the siphon tube has a first port and a second port, the first port of the siphon tube is close to the bottom of the inner cavity of the first chamber, the second port of the siphon tube passes through the body wall of the first chamber and is connected to the viscosity detection chamber, and the second port is lower than the first port; a sampling interface connected to the ink system is provided on the first chamber, the bottom surface of the first chamber is higher than the bottom surface of the viscosity detection chamber, the volume of the first chamber is larger than the volume of the viscosity detection chamber, and a first overflow balancing port connected to the top of the viscosity detection chamber is provided on the top of the first chamber; the throttling drain pipe is provided at the bottom of the viscosity detection chamber, and the other end of the throttling drain pipe is connected to the top of the mixing cylinder; a second overflow balancing port connected to the top of the mixing cylinder is provided on the side wall of the viscosity detection chamber.

2. The viscosity detection device of the inkjet printer according to claim 1, characterized in that: The siphon tube is an inverted U-shaped tube, and the highest position of the inverted U-shaped tube is lower than the first overflow balance port.

3. The viscosity detection device for inkjet printer according to claim 1 or 2, characterized in that: Also includes: A flow-limiting damping tube is serially connected to the pipeline to which the sampling interface is connected.

4. The viscosity detection device for inkjet printer as described in claim 3, characterized in that: The liquid level sensor includes a high liquid level switch and a low liquid level switch.

5. The viscosity detection device for inkjet printer as claimed in claim 4, characterized in that: The sensing liquid level of the high liquid level switch is lower than the position of the second overflow balancing port.

6. The viscosity detection device for inkjet printer as claimed in claim 5, characterized in that: The invention also includes an air pressure balance port which is opened on the top of the mixing cylinder and connects the mixing cylinder with the atmosphere.

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