JP6401602B2 - Sub tank and printer - Google Patents

Description

  The present application relates to a subtank and a printer used in an ink jet printer.

  In recent years, printers employing an ink jet method have been increasingly popular. Inkjet printers have various contrivances regarding the handling of ink (see, for example, Patent Documents 1-3).

Special table 2003-53743 gazette Japanese Utility Model Publication No. 3-77642 JP-A-62-204950

  An ink jet printer is provided with an ink jet head. The ink jet head has finely formed ejection ports for ejecting ink and ink chambers for pressurizing ink ejected from the ejection ports. Therefore, when air bubbles are mixed into the ink supplied to the ink jet head, the air bubbles impede the flow of ink, and the ink jet head cannot operate normally.

  By the way, in the case of a complicated device such as an industrial ink jet printer that handles a large amount of ink with a plurality of ink jet heads, the ink pressure supplied to the ink jet head is maintained within a specified range. A sub tank may be provided between the head and the main tank for storing ink. In the case of a printer having a sub-tank, even if bubbles are included in the ink supplied from the main tank to the sub-tank, the ink-jet head can operate normally if the bubbles are removed from the ink supplied from the sub-tank to the ink-jet head. It is. Therefore, it may be possible to install auxiliary equipment that degass the ink in the sub tank and try measures to remove bubbles contained in the ink in the sub tank or to reduce the generation of bubbles by mixing defoaming agent in the ink. It is done. However, if there are many air bubbles contained in the ink sent from the main tank, these measures may not sufficiently degas the ink in the sub tank. In addition, the use of an antifoaming agent restricts the use of ink that does not chemically match the antifoaming agent, which can contribute to a decrease in printing quality and an increase in running cost.

  Therefore, the present application provides a subtank and a printer that can suppress bubbles mixed in the liquid phase portion in the subtank in the process in which the ink sent from the main tank flows into the subtank.

  The present application discloses the following sub-tank. That is, the present application relates to a sub tank main body provided in the middle of an ink path connecting between an ink jet head of a printer and a main tank for storing ink, and an opening from an upper portion of the sub tank main body toward an internal space of the sub tank main body. And an ink outlet from which the ink sent from the main tank flows out, and an edge of the ink outlet toward the bottom of the internal space, and the tip is closer to the bottom than the prescribed liquid level. A subtank comprising an ink guide is disclosed.

  Moreover, this application discloses the printer provided with the said sub tank.

  If it is said subtank and a printer, the bubble mixed in the liquid phase part in a subtank in the process in which the ink sent from a main tank flows in into a subtank can be suppressed.

FIG. 1 is a diagram illustrating an example of an internal structure of a sub tank according to the embodiment. FIG. 2 is a diagram showing an example of a sub tank in which the lid is assembled to the body and the sub tank is filled with ink up to a specified liquid level. FIG. 3 is an example of a configuration diagram of a printer including a sub tank according to the present embodiment. FIG. 4 is a diagram illustrating an example of bubble behavior realized in the sub-tank according to the embodiment. FIG. 5 is a diagram illustrating an example of the behavior of bubbles when the tip of the ink guide portion is not immersed in the ink level in the sub tank. FIG. 6 is a diagram illustrating an example of the behavior of bubbles when the outflow port from which ink flows out is completely immersed in the liquid phase portion of the tank. FIG. 7 is a diagram illustrating an example of the behavior of bubbles when ink is caused to flow out from an outlet that does not have a tapered tip.

  Hereinafter, embodiments will be described. The embodiment described below is merely an example, and the technical scope of the present disclosure is not limited to the following aspect.

  FIG. 1 is a diagram illustrating an example of an internal structure of a sub tank according to the embodiment. The sub tank 1 is a tank including a sub tank main body 2 having a body portion 3 and a lid portion 4, an ink outlet 5 formed in the lid portion 4, and an ink guide portion 6. The sub tank main body 2 is provided in the middle of an ink path connecting between the ink jet head of the printer and a main tank for storing ink.

  The trunk portion 3 of the sub tank main body 2 is a cylindrical member having a bottom surface 7 inside and having an upper portion opened. The lid portion 4 of the sub tank main body 2 is a member that closes the opening on the upper side of the trunk portion 3, and can be fastened with a bolt 9 to a flange portion 8 provided on the upper portion of the trunk portion 3. The lid portion 4 has a circular base portion 10 that is fastened with bolts 9 to the upper portion of the body portion 3, and a columnar protrusion portion 11 that protrudes from the base portion 10 toward the bottom portion of the internal space of the sub-tank body 2. doing.

  The ink outlet 5 formed in the middle of the protruding portion 11 of the lid portion 4 opens from the upper part of the sub tank main body 2 toward the internal space of the sub tank main body 2, and the ink sent from the main tank flows out. The outer peripheral surface of the protrusion 11 below the ink outlet 5 forms an ink guide 6 that protrudes from the edge of the ink outlet 5 toward the bottom of the internal space of the sub tank body 2. The outer peripheral surface of the protrusion 11 below the ink outlet 5 is tapered toward the bottom of the internal space of the sub-tank main body 2, and the tip is designed so as to reach the bottom of the specified liquid level. ing.

The sub tank 1 is provided with a liquid level sensor 12 that measures the liquid level of the ink in the sub tank 1. As the liquid level sensor 12, various types such as a float type, an electrode type, an ultrasonic type, and a capacitance type can be applied. In addition, a pipe connection port 13 </ b> D to which a pipe or the like leading to the ink jet head is connected is provided at the bottom of the sub tank 1.

  FIG. 2 is a view showing an example of the sub tank 1 in a state where the lid portion 4 is assembled to the body portion 3 and the sub tank 1 is filled with ink up to a predetermined liquid level. When the sub tank 1 is filled with ink to a specified liquid level, the tip of the ink guide portion 6 protruding from the edge of the ink outlet 5 toward the bottom of the internal space of the sub tank main body 2 is immersed in the ink 14. In addition, in FIG. 2, although the figure which saw through the inside of the subtank 1 is shown, it is not intending that the trunk | drum 3 is formed with a transparent member. The material which comprises the cover part 4 and the trunk | drum 3 can be selected suitably, and a metal, resin, and other various non-transparent members are applicable. In FIG. 2, three pipe connection ports 13 </ b> I communicating with the ink outlet 5 are illustrated. Although the three pipe connection ports 13I communicate with the internal space of the sub tank 1, each of the three pipe connection ports 13I is not assumed to be used for connection to the main tank. Nothing is connected to at least one of the three pipe connection ports 13I, and the sub tank 1 is used for air release. In addition, any of the three pipe connection ports 13I may be configured such that, for example, the ink after the deaeration process that returns from the device that degass the ink in the sub tank 1 flows.

  FIG. 3 is an example of a configuration diagram of the printer 20 including the sub tank 1 according to the present embodiment. The printer 20 is an ink jet printer. For example, as shown in FIG. 3, as shown in FIG. 3, the main tank 21, the sub tank 1 into which the ink sent from the main tank 21 flows, the ink jet head that prints with the ink sent from the sub tank 1. 22 and a control device 23 are provided. A pump 25 is provided in the middle of a pipe 24 that forms an ink path from the main tank 21 to the sub tank 1. The pump 25 operates based on a signal output from the control device 23 according to the liquid level in the sub tank 1. The control device 23 appropriately operates the pump 25 so that the liquid level in the sub tank 1 does not fall below a prescribed liquid level, and controls the operation of the inkjet head 22 and the operation of a paper feed mechanism (not shown). .

  The specified liquid level of the sub-tank 1 applied to the printer 20 is a relative height difference (liquid head pressure) relative to the inkjet head 22 so that the pressure of the ink supplied to the inkjet head 22 is within a specified range. It is determined based on. The relative height difference between the inkjet head 22 and the prescribed liquid level of the sub tank 1 is in accordance with the specifications of the manufacturer of the inkjet head 22. As an example of the specifications of the inkjet heads distributed in the market, for example, there is a specification in which the liquid level of the sub tank is set to be lower by about 30 to 50 mm than the inkjet head.

  When the sub tank 1 according to the embodiment is applied to the printer 20, the ink in the sub tank 1 is kept at a specified liquid level. Thus, the tip of the ink guide 6 is maintained in a state where it is immersed in the ink level in the sub tank 1. Therefore, when air bubbles generated by the air remaining in the pipe 24 that forms the ink path from the main tank 21 to the sub tank 1 and the air bubbles mixed with the ink in the main tank 21 flow into the sub tank 1, the following occurs. Show good behavior.

FIG. 4 is a diagram illustrating an example of bubble behavior realized in the sub-tank 1 according to the embodiment. In the sub tank 1 according to the present embodiment, the ink guide 6 is formed downward from the edge of the ink outlet 5 from which the ink sent from the main tank 21 flows out, and the tip of the ink guide 6 is tapered. It has become. Therefore, the ink that has flowed downward from the ink outlet 5 is in a state where it slightly spreads on the surface of the ink guide 6. On the other hand, the bubbles contained in the ink try to maintain a spherical shape and size even if they exit from the ink outlet 5. For this reason, bubbles contained in the ink are deposited on the surface of the ink in the process in which the ink exits from the ink outlet 5 and spreads on the surface of the ink guide 6. The air bubbles contained in the ink fall along with the ink flowing down through the ink guide 6 while being deposited on the surface of the ink. The bubbles contained in the ink float on the liquid level in the sub tank 1. Bubbles floating on the liquid level in the sub tank 1 diffuse to the liquid level and eventually disappear.

  FIG. 5 is a diagram illustrating an example of bubble behavior when the tip of the ink guide 6 is not immersed in the ink level in the sub tank 1. For example, when the liquid level in the subtank 1 becomes lower than the standard for some reason and the tip of the ink guide 6 is not immersed in the ink level in the subtank 1, the ink travels through the ink guide 6 and enters the subtank 1. Can not fall on the ink level. Therefore, the ink that falls to the liquid level is dripped after having accumulated to some extent at the lower end of the ink guide 6. For this reason, bubbles deposited in the process of flowing down along the surface of the ink guide 6 are likely to accumulate at the lower end of the ink guide 6.

  FIG. 6 is a diagram illustrating an example of the behavior of bubbles when the outflow port from which ink flows out is completely immersed in the liquid phase portion of the tank. For example, when the outflow port from which the ink flows out is completely immersed in the liquid phase portion of the tank, the bubbles coming out from the outflow port gradually spread to the liquid phase portion and then gradually float and deposit on the liquid surface. Therefore, foaming in the liquid phase part of the tank and the vicinity of the ink liquid level is large.

  FIG. 7 is a diagram illustrating an example of the behavior of bubbles when ink is caused to flow out from an outlet that does not have a tapered tip. For example, when the tip of the ink outlet is not tapered, and the outlet is not immersed in the liquid level of the ink in the tank, bubbles deposited at the outlet are less likely to drop. Therefore, the bubbles that flow out one after another from the outlet gradually gather and grow, and it is easy to form relatively large sized bubbles. As a result, large bubbles that do not easily disappear may be formed on the liquid level of the tank.

  On the other hand, in the case of the subtank 1 according to the embodiment, when the tip of the ink guide portion 6 is tapered and immersed in the liquid surface of the ink, bubbles contained in the ink flowing out from the ink outlet 5 are generated in the subtank. It floats on the liquid surface in 1 and is easy to diffuse and disappear easily. Therefore, in the sub tank 1 according to the embodiment, it is possible to suppress bubbles mixed in the liquid phase portion in the sub tank in the process in which the ink sent from the main tank 21 flows into the sub tank 1. As a result, the possibility of bubbles being mixed into the ink supplied from the sub tank 1 to the inkjet head 22 can be reduced, and the occurrence of malfunction of the inkjet head 22 can be suppressed as much as possible.

  For example, in the case of a complicated device that handles a large amount of ink with a plurality of ink jet heads, such as an industrial ink jet printer, the configuration of the device is complicated, so that a pipe through which the ink flows is complicatedly stretched or An elbow or the like is easily provided in the middle of the pipe. Therefore, in the case of an industrial inkjet printer, the air remaining in the ink flow path cannot be ignored. Bubbles caused by air remaining in the path through which the ink flows are particularly remarkable at the initial stage when the ink flow is started. However, in the present embodiment, attention is paid to the sub tank used because it is an industrial inkjet printer, and by providing the sub tank with a defoaming function, the bubbles are eliminated without causing an increase in the number of parts. The occurrence of malfunction of the inkjet head is suppressed as much as possible.

  In the present embodiment, the sub tank main body 2 has a cylindrical outer shape as a whole, but the sub tank disclosed in the present application is not limited to such a form. The sub-tank disclosed in the present application may have, for example, a rectangular parallelepiped or a cubic outline as a whole, or may have another outline.

Moreover, in this embodiment, although the liquid level sensor 12 was provided in the protrusion part 11 of the cover part 4, a liquid level sensor is not limited to such a form. The sub-tank liquid level sensor disclosed in the present application may be provided beside the protrusion 11 of the lid 4 or may be provided at a site other than the lid 4, for example. Moreover, the liquid level sensor may be abbreviate | omitted in the subtank disclosed by this application. In this case, the liquid level in the sub tank may be measured by various sensors provided around the sub tank, for example, or the flow level sensor provided in the path of the pipe connected to the sub tank may be used. The liquid level in the sub tank may be indirectly measured or estimated using a pressure sensor or the like.

  Further, in the present embodiment, the seven pipe connection ports 13D are illustrated at the bottom of the sub tank 1, but the sub tank disclosed in the present application is not limited to the one provided with the seven pipe connection ports 13D. The subtank disclosed in the present application may have as many pipe connection ports as the number of ink jet heads used in the printer, and may include six or less pipe connection ports, or may include seven or more pipe connection ports. .

  In the present embodiment, no special mention is made of an auxiliary device that degass the ink in the sub-tank 1. However, an auxiliary device that degass the ink in the tank may be provided in the sub-tank disclosed in the present application. As an auxiliary machine for degassing the ink in the tank, for example, a degassing module using a hollow fiber that transmits gas and does not transmit liquid, and other various types distributed in the market can be applied.

1. Sub tank: 2. Sub tank body: 3. Body part: 4. Lid part: 5. Ink outlet: 6. Ink guide part: 7. Bottom face: 8. Flange part: 9. · Bolt: 10 · · Base: 11 · · Projection: 12 · · Liquid level sensor: 13I, 13D · · Pipe connection port: 14 · · Ink: 20 · · Printer: 21 · · Main tank: 22 · · Inkjet Head: 23 ... Control device: 24 ... Pipe: 25 ... Pump

Claims (6)

A sub tank main body provided in the middle of an ink path connecting between the ink jet head of the printer and a main tank for storing ink;
An ink outlet opening from the upper part of the sub tank main body toward the internal space of the sub tank main body, and the ink sent from the main tank flows out;
An ink guide formed from the edge of the ink outlet to the bottom of the internal space, the tip being closer to the bottom than the prescribed liquid level ,
The ink outlet is a surface of a member that forms the ink guide, and is open on a surface that forms the ink guide.
Sub tank. The ink guide portion is tapered toward the bottom of the internal space.
The sub tank according to claim 1. The sub-tank main body includes a body portion having a bottom surface inside and an upper portion opened, and a lid portion for closing an upper opening portion of the body portion,
The ink outlet and the ink guide are formed on the lid.
The sub tank according to claim 1 or 2. The lid portion has a circular base portion fastened to the upper portion of the body portion, and a columnar protrusion portion that protrudes from the base portion toward the bottom portion of the internal space,
The ink guide portion is formed on the outer peripheral surface of the protrusion.
The sub tank according to claim 3. The sub tank further includes a liquid level sensor connected to a control device that controls the amount of ink supplied from the main tank to the sub tank so that the liquid level of the ink in the sub tank becomes the specified liquid level.
The sub tank according to any one of claims 1 to 4.   A printer comprising the sub-tank according to any one of claims 1 to 5.

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