CN1253075A - pressure control device - Google Patents

Abstract

A pressure controller is arranged at the bottom of ink storage tank of ink-jet pen, the top of jet hole is arc surface, the ball is placed on the arc surface and contacted with it, the ball is contacted with jet hole by line, a reed is fixed on the bottom of ink storage tank, the reed has the first part and the second part, the first part is contacted with the ball tightly, the second part is contacted with the press plate in ink storage tank, when the press plate is pressed to reed by the expansion of air bag, the second part of reed is pressed to separate the first part from the ball, at this time, a gap is generated between ball and jet hole, the air outside enters the ink storage tank to change the pressure in the storage tank.

Description

pressure control device

The invention relates to a pressure control device, in particular to a pressure control device for the fluid in the ink storage tank of an inkjet pen.

In the existing inkjet printing technology, the control method for outputting the ink from the ink storage tank to the printing paper is the required flow control method.

Although the print head of the flow control method can effectively obtain ink from the storage tank in the pen to eject ink droplets, the flow control method requires a control mechanism so that the ink will not ooze out of the print head when the print head is not printing. head. This control mechanism usually provides a slight negative pressure at the print head to prevent ink from leaking out of the print head. The so-called negative pressure refers to the formation of a partial vacuum in the ink storage tank. When measuring the negative pressure, it is expressed as a positive value, so the increase of the negative pressure represents the increase of the vacuum degree, and the increase of the negative pressure can prevent the ink from flowing out of the print head. Although the increase of the negative pressure can prevent the ink from flowing out of the print head, if the negative pressure is too large, the print head cannot overcome the negative pressure and the ink droplets cannot be ejected. On the other hand, the negative pressure in the ink storage tank of the inkjet pen must be able to make corresponding adjustments with the change of the surrounding environment pressure, so that the negative pressure can be kept within an appropriate range, so that the inkjet pen can operate normally. For example, when the ambient pressure drops, the negative pressure value to prevent ink from leaking out of the print head will be larger.

The prior art used to regulate the negative pressure in the ink reservoir is achieved by a mechanism in the ink reservoir called a regulator. This regulator is generally an elastic air bag, and its mechanism is designed so that the elastic air bag of the regulator can change between the maximum capacity and the minimum capacity of the air bag, and the volume of the ink storage tank is also changed accordingly to adjust the ink storage tank. negative pressure value. For example, when the pressure of the surrounding environment drops, the negative pressure in the inkjet pen will decrease accordingly. At this time, the regulator will start to act (the elastic air bag shrinks) to increase the capacity of the ink storage tank, and the negative pressure will also increase accordingly, making the ink Not to leak.

However, while the regulator's elastic air bag can successfully adjust the volume of the ink tank, some limitations still exist. Generally speaking, the maximum expansion of the elastic airbag has its limit. Therefore, when the ink is consumed to a certain extent, the volume of the ink storage tank cannot be changed because the elastic airbag has reached the maximum expansion. Therefore, as the ink decreases, the negative pressure exceeds the allowable range and the print head cannot overcome the negative pressure, so that the ink droplets cannot be ejected, and the ink cannot be completely used up.

To address the above problems, some inkjet pens employ a "bubble generator" device. The bubble generator has a spray hole, through which the ink tank communicates with the surrounding environment. After the size of the nozzle hole is designed, the ink can be gathered in the nozzle hole to form a liquid seal by capillary force. When the outside air overcomes the liquid seal, it will enter the ink storage tank in the form of air bubbles, thereby reducing the negative pressure in the storage tank. After the air bubbles enter the storage tank, the negative pressure value decreases and is less than the capillary force, so that the liquid-state airtight state is re-established, preventing the air bubbles from continuing to enter.

Bubble generators used in inkjet pens usually have several requirements. First of all, the bubble generator must be able to reliably control the negative pressure value of the ink storage tank when the bubbles enter. Secondly, the range of negative pressure must be able to be controlled, that is, after the negative pressure begins to drop when the bubbles start to enter the ink tank, the bubble generator must prevent the bubbles from continuing to enter the storage tank at an appropriate time, so as to maintain a proper negative pressure in the storage tank. Another requirement is self-wetting capability. When the ink in the ink tank is consumed to a certain extent or the angle of the inkjet pen is changed so that the bubble generator is no longer immersed in the ink, the liquid type The seal is still effective and can block the entry of air bubbles.

Please refer to FIG. 1 , which is the prior art of US Patent No. 5,526,030. The storage tank 102 of the existing inkjet pen 100 has a bubble generator mainly composed of a nozzle hole 104 and a ball 106 , and the ball 106 is placed in the nozzle hole 104 . Please refer to FIG. 2 , which shows the structure around the bubble generator. Equidistant ribs 108 are designed around the inner wall of the spray hole 104 for fixing the ball 106 . The annular gap 110 formed by the ball 106 and the nozzle hole 104 is where the bubbles are generated.

The above-mentioned air bubble generator generally meets several requirements of an air bubble generator used in an inkjet pen. The method of controlling air bubbles entering the ink storage tank 102 is determined according to the surface tension of the ink itself, the hydrostatic pressure of the ink, and the gap between the ball 106 and the nozzle hole 104 . The higher the surface tension of the ink or the smaller the gap, the higher the negative pressure of the ink tank required when air bubbles enter. In addition, the hydrostatic pressure of the ink itself will also affect the negative pressure value required for air bubbles to enter. When the ink decreases, the smaller the hydrostatic pressure of the ink, the lower the negative pressure value required for bubble formation, so the main disadvantages of the above-mentioned prior art are:

1. The negative pressure value of the ink storage tank when air bubbles enter is related to the surface tension of the ink. When inks of different properties are used, the negative pressure value of the ink storage tank required when the bubbles enter will change accordingly, so the gap between the ball and the nozzle needs to be readjusted to maintain the negative pressure of the ink storage tank required for the bubbles to enter. The change of the pressure value will not be too large, but can meet the best printing quality.

2. The negative pressure value of the ink storage tank when air bubbles enter is related to the hydrostatic pressure value of the ink. When the residual amount of ink is less, the static pressure of the ink is lower, and the air bubbles are thus easier to enter the ink storage tank, because the required negative pressure value is reduced. This phenomenon will cause the negative pressure in the ink tank to decrease as the ink is reduced, and the range of ambient pressure that the regulator can regulate will be reduced.

3. In order to make the negative pressure of the ink storage tank when air bubbles enter the designed value, the gap between the ball and the nozzle hole must be precisely controlled, which will cause difficulties in manufacturing and assembly.

The object of the present invention is to provide a pressure control device, which will not cause the negative pressure in the ink storage tank to change too much due to the exhaustion of ink.

Another object of the present invention is to provide a pressure control device, which has nothing to do with the type of liquid in the storage tank, and will not affect the change of negative pressure due to the type of ink.

The object of the present invention is achieved by providing a pressure control device, placed in a closed storage tank, the closed storage tank stores ink and maintains a negative pressure, the pressure control device includes: a nozzle hole, located in the The bottom of the airtight storage tank, and the top of the spray hole is an arc surface; a ball is located at the top of the spray hole, and forms a circular line contact with the spray hole to block the inside and outside of the closed storage tank flow; and an elastic device having a first part and a second part connected to each other, the first part is in close contact with the ball and the second part is coupled with a regulator in the closed storage tank, so that when The regulator causes the second part of the elastic device to be pushed due to pressure fluctuations, so that the first part is not in contact with the ball.

The present invention also provides an inkjet ink cartridge, comprising: an airtight storage tank used for ink storage, and a negative pressure is maintained in the airtight storage tank; a pressure control device is located in the airtight storage tank, The pressure control device includes: a spray hole, located at the bottom of the airtight storage tank, and the top of the spray hole is an arc surface, a ball, located at the top of the spray hole, and forms an annular shape with the spray hole Line contact to block the internal and external communication of the airtight storage tank, and an elastic device with a first part and a second part connected to each other, the first part is in close contact with the ball and the second part is in close contact with the airtight storage tank an adjuster in the groove is coupled so that when the adjuster causes the second part of the elastic device to be pushed due to a change in pressure, the first part is not in contact with the ball; and a print head is located at the Close the bottom of the storage tank.

The present invention also provides a pressure control method for maintaining the negative pressure of an airtight storage tank in an inkjet pen within a limited range and the airtight storage tank includes a regulator and a pressure control device, the method is : When the regulator expands to the maximum expansion, the regulator acts on the pressure control device to introduce the external gas into the closed storage tank in the form of bubbles, thereby compressing the regulator, and repeating this procedure .

The pressure control device of the present invention is used as a bubble generator. The device is arranged at the bottom of the ink storage tank of the inkjet pen. The top of the nozzle hole is an arc surface. The ball is placed on the arc surface and is in contact with it. Ideally, the contact between the ball and the orifice is a line contact. An elastic device, such as a reed, is fixed on the bottom of the ink storage tank with a fixing pin. The reed has a first part and a second part, wherein the first part and the ball are in close contact with each other; the second part is in contact with the pressure plate in the ink reservoir, and when the pressure plate is pressed against the pressure plate due to the expansion of the air bag, it will compress the reed The second part, in turn, separates the first part from the sphere. The ball will float due to the negative pressure in the ink reservoir. At this time, a gap is formed between the ball and the nozzle hole, so the outside air can enter the ink storage tank.

After the outside air enters the ink storage tank, the negative pressure in the storage tank drops, and the bag is compressed by the spring and shrinks. At this time, the reed is no longer pressed by the pressure plate, and the reed returns to its original shape due to its own elasticity and no longer deforms. . That is, the first part of the reed returns to the state of being in close contact with the ball, and the air bubbles no longer enter the storage tank.

With this device, the ink in the ink storage tank is nearly exhausted, and the negative pressure in the storage tank can be maintained within a certain range.

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

Fig. 1 is a structural diagram of an existing inkjet pen with a bubble generator;

Fig. 2 is the top view of bubble generator in Fig. 1;

Fig. 3 is a structural diagram of the pressure control device of the present invention;

Fig. 4 is the embodiment of the present invention, the schematic diagram after the adjustment bag in the black spray pen expands;

Fig. 5 is an embodiment of the present invention, a schematic diagram of the regulating bag in the inkjet pen being inflated and in contact with the pressure control device of the present invention;

Fig. 6 is a schematic diagram of the liquid closure of the bubble generator provided by the pressure control device of the present invention;

Fig. 7 is a comparison graph between the negative pressure curve of the present invention and the negative pressure curve of the prior art.

Please refer to FIG. 3 , which is a construction diagram of the pressure control device of the present invention, which is used as a bubble generator. The device is disposed at the bottom 400c of the ink storage tank 400 of the inkjet pen, please refer to FIG. 4 for a related position diagram. The tip of the nozzle hole 310 is an arc surface 312 . The ball 320 is placed on and in contact with the arcuate surface 312 . Ideally, the contact between the ball 320 and the nozzle hole 310 is a line contact. An elastic device 330 , such as a reed, is fixed on the bottom 400c of the ink storage tank by a fixing pin 332 . The reed 330 has a first part 330a and a second part 330b, wherein the first part 330a and the ball 320 are in close contact with each other; When the pressure plate is pressed, it will press the second part 330b of the reed 330 , and then separate the first part 330a from the ball 320 . At this time, the ball 320 will float due to the negative pressure in the ink storage tank.

Please refer to FIG. 4 , which is an ink storage tank 400 applying the pressure control device 300 of the present invention. The ink storage tank 400 is a closed chamber surrounded by side walls 400 a , 400 b , 400 c and a cover 405 . There is a regulator 410 in the ink storage tank 400 , and the pressure regulator 410 is composed of an elastic device, which includes a pressing plate 412 , a spring 414 , and a bag 416 . The bag 416 includes a first chamber 416a and a second chamber 416b. The first chamber 416a allows the fluid in the bag 416 to communicate with the outside through a conduit 418, and the conduit 418 passes through the cover 405 and is tightly sealed therewith. There is an opening 420 between the first chamber 416a and the second chamber 416b, for the fluid in the bag to communicate between the first chamber 416a and the second chamber 416b.

One side of the bag 416 is in contact with the inner surface of the side wall 400 b of the ink reservoir 400 , and the other side of the bag 416 is in contact with the first surface 412 a of the platen 412 . The second surface 412 b of the pressing plate 412 is supported by one end of the spring 414 . The other end of the spring 414 is supported by the inner surface of the side wall 400 a of the ink storage tank 400 .

Ink is injected into the ink storage tank 400 through the ink injection port 430 and sealed with a sealing cover 432 to completely isolate the ink storage tank 400 from the outside. At this time, there is a minimum negative pressure in the ink storage tank 400 . This minimum negative pressure can prevent ink from bleeding from the print head 440 when the print head 440 is in a static state without printing.

When the inkjet pen is printing, the vacuum in the ink storage tank 400 is increased due to the gradual depletion of ink, and the negative pressure increases accordingly. Because the bag 416 communicates with the outside, the pressure therein is equal to the outside atmospheric pressure and greater than the pressure in the ink storage tank. The bag 416 is therefore inflated, as shown in FIG. 4 . After the bag 416 is inflated and the pressure plate 412 squeezes the spring 414, the volume of the ink storage tank 400 is reduced, and its vacuum degree is relatively reduced, which can effectively suppress the effect of negative pressure increase and prevent ink from being unable to print from the print head 440. out.

When the external environment changes to reduce the pressure, such as during air transportation. At this time, because the bag 416 communicates with the outside, the pressure therein is equal to the outside atmospheric pressure and drops accordingly. Therefore, the bag 416 will be compressed because the pressure in the ink storage tank 400 is greater than the pressure in the bag 416 , so that the restoring force of the spring 414 exerts force on the pressing plate to compress the bag 416 . After the bag 416 is compressed, the vacuum degree in the ink storage tank 400 increases, and the negative pressure relative to the external atmospheric pressure is balanced. Therefore, the negative pressure in the ink storage tank 400 will not be reduced due to the pressure drop of the environment, so the effect of negative pressure reduction can be effectively suppressed, preventing ink from seeping out from the print head 440 .

When the expansion of the bag 416 reaches the maximum, the volume of the ink storage tank 400 can no longer be changed. If the ink continues to be consumed, the negative pressure in the ink storage tank 400 will always increase and affect the printing quality.

Referring to FIG. 5 , when the bag 416 continues to expand (direction B), the bag pushes against the platen 412 . At this time, the bottom end of the pressing plate 412 is in contact with the second portion 330b of the reed 330 of the pressure control device 300 , and the first portion 330a of the reed 330 is forced to separate from the ball 320 due to the pressing of the pressing plate 412 . When the reed 330 is pushed away from the ball 320, the ball 320 will float up due to the negative pressure in the ink storage tank 400. At this time, there is a gap between the ball 320 and the nozzle hole 310, so the outside air 340 Just can enter among the ink storage tank 400.

After the outside air 340 enters the ink storage tank 400, the negative pressure in the storage tank drops, the bag 416 is compressed by the spring 414 and shrinks, and the pressure plate 412 moves in the direction A, and the reed 330 is no longer pressed by the pressure plate 412 At this time, the reed 330 returns to its original shape due to its own elastic force and is no longer deformed (as shown in FIG. 4 ). That is, the first portion 330 a of the reed 330 returns to the state of being in close contact with the ball 320 , and the air bubbles no longer enter the storage tank 400 .

When the amount of ink decreases again, the above-mentioned operations are carried out, as in the situation shown in Figure 5, and then the state in Figure 4 is restored. Continues continuously until the ink is exhausted.

In addition, the pressure control device of the present invention can provide a liquid-type sealing device and self-lubricating ability. As shown in Figure 6, between the ring-shaped contact line of the ball 320 and the nozzle hole 310 and the top of the nozzle hole 310, a certain amount of ink 350 remains at this position due to the surface tension of the ink itself, which will constitute a It is a liquid closed state and has a self-lubricating function.

As can be seen from the above, the device of the present invention has the following benefits and advantages:

1. The pressure control device of the present invention prevents the negative pressure of the ink storage tank from being affected by the surface tension of the ink. According to the actual test results, the pressure control device in the prior art has a difference of 2-3 cm-WC in the negative pressure of the ink storage tank due to the water or ink in the storage tank.

2. pressure control device of the present invention makes the negative pressure variation range in the ink storage tank less, as shown in Figure 7, the negative pressure variation range of prior art (curve I) is between 18～13cm-WC, has 5cm -The variation of WC; and the test result (curve II) of the present invention is between 21～18cm-WC, and its variation drops to 3cm-WC, so higher printing quality can be obtained.

3. The pressure control device of the present invention does not need to precisely control the gap between the ball and the nozzle hole, so that the negative pressure value when air bubbles enter the ink storage tank is the designed value.

4. The pressure control device of the present invention is simple in structure and does not occupy the volume of the ink tank, and has the advantages of easy manufacture and low production cost.

In summary, although the present invention has been disclosed in conjunction with a preferred embodiment, it is not intended to limit the present invention. Those skilled in the art can make various modifications and changes without departing from the spirit and scope of the present invention. modification, so the protection scope of the present invention should be regarded as the scope defined by the appended claims.

Claims (11)

1. A pressure control device placed in an airtight storage tank, the airtight storage tank stores ink and maintains a negative pressure, it is characterized in that the pressure control device includes: A spray hole is located at the bottom of the closed storage tank, and the top of the spray hole is an arc surface; A spherical ball is located at the top of the nozzle hole and forms a ring-shaped line contact with the nozzle hole to block the internal and external communication of the closed storage tank; and An elastic device has a first part and a second part connected to each other, the first part is in close contact with the ball and the second part is coupled with a regulator in the airtight storage tank, so that when the regulator The second part of the elastic device is pushed due to the change of pressure, so that the first part is not in contact with the ball. 2. The pressure control device according to claim 1, characterized in that the outside of the airtight storage tank is an atmospheric environment. 3. The pressure control device according to claim 1, wherein the reed is made of stainless steel. 4. The pressure control device of claim 1, wherein the regulator further comprises: a pressure plate; a stretchable bag coupled with one side wall of the closed storage tank and one side of the pressing plate; the stretchable bag also has a conduit passing through the closed storage tank to communicate with the outside world; and A spring, the two ends of the spring are respectively coupled with the other side of the pressing plate and the other side wall of the airtight storage tank. 5. An inkjet type ink cartridge, comprising: A closed storage tank is used for ink storage, and a negative pressure is maintained in the closed storage tank; A pressure control device located in the closed storage tank, characterized in that the pressure control device includes: A spray hole is located at the bottom of the closed storage tank, and the top of the spray hole is an arc surface, a ball, located at the top of the nozzle hole, and forms a ring-shaped line contact with the nozzle hole, so as to block the internal and external communication of the closed storage tank, and An elastic device has a first part and a second part connected to each other, the first part is in close contact with the ball and the second part is coupled with a regulator in the airtight storage tank, so that when the regulator the second part of the elastic means is pushed due to the change of pressure so that the first part is out of contact with the ball; and A printing head is located at the bottom of the closed storage tank. 6. The inkjet ink cartridge as claimed in claim 5, wherein the outside of the airtight storage tank is an atmospheric environment. 7. The inkjet ink cartridge as claimed in claim 5, wherein the spring is made of stainless steel. 8. The inkjet ink cartridge of claim 5, wherein the regulator further comprises a pressure plate; a stretchable bag coupled with one side wall of the closed storage tank and one side of the pressing plate; the stretchable bag also has a conduit passing through the closed storage tank to communicate with the outside world; and A spring, the two ends of the spring are respectively coupled with the other side of the pressing plate and the other side wall of the airtight storage tank. 9. A pressure control method for maintaining the negative pressure of an airtight storage tank in an inkjet pen within a limited range and the airtight storage tank includes a regulator and a pressure control device, characterized in that the the way is: When the regulator expands to the maximum expansion amount, the regulator acts on the pressure control device to introduce external gas into the closed storage tank in the form of bubbles, thereby compressing the regulator, and this procedure is repeated. 10. The pressure control method according to claim 9, wherein the regulator comprises: a pressure plate; a stretchable bag coupled with one side wall of the closed storage tank and one side of the pressing plate; the stretchable bag also has a conduit passing through the closed storage tank to communicate with the outside world; and A spring, the two ends of the spring are respectively coupled with the other side of the pressing plate and the other side wall of the airtight storage tank. 11. The pressure control method according to claim 9, wherein the pressure control device comprises: A spray hole is located at the bottom of the closed storage tank, and the top of the spray hole is an arc surface; A spherical ball is located at the top of the nozzle hole and forms a ring-shaped line contact with the nozzle hole to block the internal and external communication of the closed storage tank; and An elastic device has a first part and a second part connected to each other, the first part is in close contact with the ball and the second part is coupled with the regulator, so that when the regulator changes due to pressure The second part of the elastic means is pushed so that the first part is out of contact with the ball.

Images