JP2009274384A - Ink tank, and ink reserving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a dissolved oxygen amount from increasing, without changing an ink characteristic. <P>SOLUTION: This ink tank 4 for reserving ink 6 supplied to an inkjet head is provided with a tank body 7 constituted of a nonsealed type container and for reserving the ink 6, in a bulk ink supply system. A plurality of beads 8 having a specific gravity lower than that of the ink 6 reserved in the tank body 7 is stored in the tank body 7. The beads 8 float on a surface of the reserved ink 6 in the tank body 7, in the ink tank 4 constituted by this manner, and the surface of the ink 6 is brought into a state covered with the beads 8. A contact area of the ink 6 with air gets narrow thereby, to restrain oxygen in the air from being dissolved into the ink 6 reserved in the tank body 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a non-sealed ink tank that stores ink to be supplied to an inkjet head by a bulk ink supply system of an inkjet printer, and an ink storage method that stores ink in the ink tank.

In general, in an inkjet printer or the like that consumes a large amount of ink, a bulk ink supply system that supplies ink from an ink tank to an inkjet head is considered. This bulk ink supply system includes an ink tank that stores a large amount of ink separately from the ink jet head, and discharges ink from the nozzles of the ink jet head by supplying ink from the ink tank to the ink jet head. Can be done.
JP 2007-050555 A

  By the way, in the bulk ink supply system, in order to maintain the quality of the ink and prevent the nozzles of the inkjet head from being clogged by bubbles generated from the ink, the ink stored in the ink tank should have as little dissolved oxygen as possible. desirable. However, since the ink tank is provided with an ink replenishing port for replenishing ink and is not sealed, air flows into the ink tank from the ink replenishing port. For this reason, there is a problem that the oxygen in the air dissolves in the ink stored in the ink tank, so that the amount of dissolved oxygen in the ink increases and the ink ejection stability decreases.

  In Patent Document 1, it is described that a protective liquid having a specific gravity lighter than that of ink is provided in a sub tank provided with an air communication port. However, in the tank described in Patent Document 1, since the ink and the protective liquid are liquids, the ink and the protective liquid are likely to be mixed, and until the mixed ink and the protective liquid are completely separated. Since a considerable amount of time is required, there is a problem that the ink characteristics may change.

  Accordingly, an object of the present invention is to provide an ink tank and an ink storage method that can suppress an increase in the amount of dissolved oxygen without changing the characteristics of the ink.

  An ink tank according to the present invention is a non-sealed ink tank that is used in a bulk ink supply system that supplies ink to an ink jet head of an ink jet printer and stores ink supplied to the ink jet head. And a solid air shield housed in the tank body and having a specific gravity smaller than that of the ink.

  According to the ink tank of the present invention, since the solid air shield having a specific gravity smaller than that of the ink is accommodated in the tank main body, the ink stored in the tank main body includes these solid air shields. It floats so as to cover the surface of the ink, and the contact area between the ink and air becomes small. For this reason, even if air flows into the tank body, it is possible to suppress the oxygen in the air from being dissolved in the ink stored in the tank body. In addition, since the solid air shield is solid, it is difficult to mix with the liquid ink, so that the ink characteristics can be prevented from changing. Even if the tank body is replenished with ink, the replenished ink is submerged and stored in the tank body without being blocked by the solid air shield, and then the solid air is driven by the replenished ink. Even if the shield is submerged in the ink, the solid air shield can quickly rise to the surface of the ink, so that the contact time between the ink and air can be minimized. As described above, according to the ink tank of the present invention, it is possible to suppress an increase in the dissolved oxygen amount of the ink stored in the tank body without changing the ink characteristics.

  In this case, the tank body preferably contains a number of solid air shields covering the surface of the ink stored in the tank body. According to this ink tank, since the surface of the ink stored in the tank main body is covered by the solid air shield accommodated in the tank main body, the contact area between the ink and air can be extremely reduced, and the tank main body An increase in the amount of dissolved oxygen in the stored ink can be further suppressed.

  The tank body is provided with a supply port for supplying ink to the ink jet head, and the solid air shield is preferably formed with an outer diameter larger than the inner diameter of the supply port. According to this ink tank, since the outer diameter of the solid air shield is formed larger than the inner diameter of the supply port, the solid air shield can be used even if the remaining amount of ink stored in the tank body is reduced. Outflow from the supply port can be prevented.

  The ink storage method according to the present invention is an ink storage method that is used in a bulk ink supply system that supplies ink to an ink jet head of an ink jet printer and stores ink supplied to the ink jet head in a non-sealed ink tank. The ink is stored in the tank body in a state in which the solid air shield having a specific gravity smaller than that of the ink is accommodated in the tank body that stores the ink.

  According to the ink storage method of the present invention, since the solid air shield having a specific gravity smaller than that of the ink is accommodated in the tank body, these solid air shields are stored in the tank body in the tank body. It floats so as to cover the surface of the ink, and the contact area between the ink and air becomes small. For this reason, even if air flows into the tank body, it is possible to suppress the oxygen in the air from being dissolved in the ink stored in the tank body. In addition, since the solid air shield is solid, it is difficult to mix with the liquid ink, so that the ink characteristics can be prevented from changing. Even if the tank body is replenished with ink, the replenished ink sinks without being blocked by the solid air shield, sinks into the tank body, and is stored. Even if the solid air shield is submerged in the ink, the solid air shield can quickly rise to the surface of the ink, so that the contact time between the ink and air can be minimized. As described above, according to the ink tank of the present invention, it is possible to suppress an increase in the dissolved oxygen amount of the ink stored in the tank body without changing the ink characteristics.

  According to the present invention, an increase in the amount of dissolved oxygen can be suppressed without changing the ink characteristics.

  Hereinafter, preferred embodiments of an ink tank according to the present invention will be described in detail with reference to the drawings. In this embodiment, the ink tank according to the present invention is applied to a bulk ink supply system of an ink jet printer. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a diagram illustrating a configuration of a bulk ink supply system including an ink tank according to the present embodiment.

  As shown in FIG. 1, an ink tank 4 according to this embodiment is provided in a bulk ink supply system 1 of an ink jet printer.

  The bulk ink supply system 1 includes a plurality of inkjet heads 3a to 3d mounted on a carriage 2 that moves in the main scanning direction, ink tanks 4a to 4d that store ink to be supplied to the inkjet heads 3a to 3d, and each ink. The tanks 4a to 4d are constituted by pipes 5a to 5d that serve as flow paths for ink supplied to the inkjet heads 3a to 3d.

  Each of the inkjet heads 3a to 3d ejects yellow Y, magenta M, cyan C, and black K ink toward the platen side. That is, the inkjet head 3a ejects yellow Y ink, the inkjet head 3b ejects magenta M ink, and the inkjet head 3c ejects cyan C ink. The ink jet head 3d ejects black K ink.

  The ink tanks 4a to 4d are tanks that store ink to be supplied to the inkjet heads 3a to 3d, respectively. That is, the ink tank 4a stores yellow Y ink, the ink tank 4b stores magenta M ink, the ink tank 4c stores cyan C ink, and the ink tank 4d stores black K ink. Is to be stored. And each ink tank 4a-4d supplies the ink of each color to the inkjet heads 3a-3d via the pipes 5a-5d.

  FIG. 2 is a cross-sectional view of the ink tank. As shown in FIG. 2, the ink tanks 4 a to 4 d are provided with a tank body 7 that stores the ink 6. The tank body 7 is constituted by a non-sealed container so that the ink 6 can be replenished, and an ink replenishing port 9 is formed in the upper part of the tank body 7. In FIG. 2, the ink replenishing port 9 is formed by opening the upper portion of the tank body 7. However, the position and shape of the ink replenishing port 9 are appropriately selected.

  A supply port 10 for supplying ink 6 to the pipe 5 is formed on the bottom surface of the tank body 7. In the tank body 7, a measuring device (not shown) for measuring the storage amount (remaining amount) of the ink 6 stored in the tank body 7 is provided. Then, when it is detected by the measurement by the measuring device that the remaining amount of the stored ink 6 has become a predetermined amount or less, the ink 6 is replenished to each of the ink tanks 4a to 4d.

A plurality of spherical beads 8 are accommodated in the tank body 7. Each bead 8 is formed in a spherical shape having an outer diameter larger than the inner diameter of the supply port 10. For example, each bead 8 is formed to have a diameter of about 4 mm (5/32 inch) corresponding to a size of about several percent with respect to the surface area of the ink 6. Each bead 8 is made of a material having a specific gravity smaller than that of the ink 6 stored in the tank body 7. That is, these beads 8 are made of a substance that floats on the surface of the ink 6. Each bead 8 is
The ink 6 stored in the tank body 7 is not soaked and is made of a material that does not dissolve in the ink 6. For this reason, the beads 8 are made of a resin such as PP (polypropylene), for example.

  Further, the number of beads 8 accommodated in the tank body 7 is at least enough to spread the inner cross section of the tank body 7. That is, in the tank body 7, at least the number of the surface of the ink 6 is covered when floating on the surface of the stored ink 6.

  In the ink tank 4 configured as described above, the beads 8 float on the surface of the ink 6 stored in the tank body 7, and the surface of the ink 6 is covered with the beads 8. When the ink 6 is replenished into the tank body 7 from the ink replenishing port 9, the replenished ink 6 pushes away the beads 8 covering the surface of the ink 6 and is not blocked by the beads 8. It sinks into the main body 7 and is stored. At this time, in the tank body 7, the ink 6 is stirred by the replenished ink 6 and the beads 8 are submerged in the ink 6, but the beads 8 have a lower specific gravity than the ink 6, so Soon, the surface of ink 6 emerges. Then, the surface of the ink 6 is again covered with the beads 8.

  In order to demonstrate the effect of the present invention, the following measurements were performed.

  In the measurement, the dissolved oxygen amount of the ink stored in the container over time was measured for the purpose of evaluating the ejection stability of the bulk ink supply system. An example in which the measurement is performed is the ink tank according to the present embodiment, and a plurality of beads 8 are accommodated in a container serving as the tank body 7. The comparative example for comparison measurement with the example is a conventional ink tank, and beads are not accommodated in a container which is a tank body.

  The measurement conditions of the examples and comparative examples are as follows.

  In the examples and the cited examples, a PP container was used as the tank body 7, and the ink stored in the container was light blue (LBL) sublimation transfer ink (Sb51). In the example, beads 8 having a material of PE (polyethylene), a size of 5/32 inch, and a number of 2000 balls were accommodated in a PP (polypropylene) container.

The measurement procedure is as follows.
(1) Put 1000 cc of ink in the simple degassing layer and stir for 30 minutes using an air pump.
(2) The amount of dissolved oxygen in the ink immediately after stirring is measured. The amount of dissolved oxygen is measured at a location 1 cm from the bottom of the container of the simple degassing layer.
(3) The ink put in the simple degassing layer is stirred and then left for 2 hours to degas the ink. At this time, the simple deaeration layer is covered with a lid so that air does not flow into the simple deaeration layer.
(4) The ink put in the simple deaeration layer is slowly transferred to the ink tank of the example and the ink tank of the comparative example using a 500 cc container.
(5) Immediately after the container replacement, 1 hour, 4 hours, 20 hours, 24 hours, and 48 hours later, the dissolved oxygen amount of the ink is measured in each of the example and the comparative example. The dissolved oxygen amount is measured at a location 1 cm from the bottom of the PP container in both the examples and comparative examples.

The measurement results are shown in Table 1 and FIG. In FIG. 3, line A shows a comparative example (without beads), and line B shows an example (with beads).

  From Table 1 and FIG. 3, in the comparative example, the dissolved oxygen amount of the ink increases with time. In particular, the amount of dissolved oxygen in the ink rapidly increases after 4 hours from the transfer of the container. On the other hand, in the example, it was found that the dissolved oxygen amount of the ink did not increase so much regardless of the passage of time.

  From this measurement result, in the example, the beads are accommodated in the container, so that the contact area between the ink and the air stored in the container is reduced, and the dissolved oxygen amount of the ink increases even if time passes. It was proved that we were able to suppress this.

  As described above, according to the ink tank 4 according to the present embodiment, the beads 8 having a specific gravity smaller than that of the ink 6 are accommodated in the tank main body 7. 7 floats so as to cover the surface of the ink 6 stored, and the contact area between the ink 6 and air is reduced. For this reason, even if air flows in into the tank main body 7, it can suppress that oxygen in air melt | dissolves in the ink 6 stored by the tank main body. In addition, since the beads 8 are solid, they are difficult to mix with the liquid ink 6, so that the characteristics of the ink 6 can be prevented from changing. Even if the ink 6 is replenished to the tank body 7, the replenished ink 6 sinks and is stored in the tank body 7 without being blocked by the beads 8, and then the momentum of the replenished ink 6 is stored. Even if the beads 8 are submerged in the ink 6, the beads 8 can quickly float up to the surface of the ink 6, so that the contact time between the ink 6 and air can be minimized. Thus, according to the ink tank 4 according to the present embodiment, an increase in the dissolved oxygen amount of the ink 6 stored in the tank body 7 can be suppressed without changing the characteristics of the ink 6.

  Further, since the surface of the ink 6 stored in the tank body 7 is covered with the beads 8 accommodated in the tank body 7, the contact area between the ink 6 and air can be made extremely small and stored in the tank body 7. In addition, an increase in the amount of dissolved oxygen in the ink 6 can be further suppressed.

  Further, since the outer diameter of the bead 8 is formed larger than the inner diameter of the supply port 10, the bead 8 flows out from the supply port 10 even when the remaining amount of the ink 6 stored in the tank body 7 is reduced. Can be prevented. Thereby, it is possible to prevent the beads 8 from being clogged in the pipe 5 or the inkjet head 3.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the bead 8 is used as an example of the solid air shield, but any solid material (solid) that shields the surface of the ink 6 in the ink tank 4 from the air may be used. May be.

  In the above embodiment, the beads 8 formed in a granular sphere have been described as an example. However, any beads may be used as long as they float on the surface of the ink 6 and can cover the ink surface with a large number of solid air shields. It may be a shape. For example, the shape may be any of spherical shape, elliptical spherical shape (egg shape), polyhedron shape, plate shape, grain shape, rod shape, and thread shape.

  In the above embodiment, the beads 8 made of PE have been described as an example. However, any material may be used as long as the specific gravity is smaller than that of the ink 6, the ink 6 is less likely to permeate, and is difficult to dissolve in the ink 6. May be. For example, any shape of PE (polyethylene), PET (polyethylene terephthalate), PC (polycarbonate), acrylic, and PP (polypropylene) may be used.

  In the above embodiment, the case where a plurality of beads 8 having a diameter of about 4 mm corresponding to a size of about several percent of the surface area of the ink 6 is accommodated in the tank body 7 is described as an example. Any size and number of air shields may be accommodated in the tank body 7 as long as the surface of the ink 6 can be covered by the shield. For example, one solid air shield may be accommodated in the tank body 7 so as to cover the surface of the ink 6.

  In the above embodiment, the tank body 7 of the ink tank 4 is described as an example in which the upper part is opened. However, any shape may be used as long as it is a non-sealed type that can be replenished with the ink 6. . For example, the tank body 17 of the ink tank 14 shown in FIG. 4 or the tank body 27 of the ink tank 24 shown in FIG. 5 may be used.

  The tank body 17 shown in FIG. 4 is covered with a casing at the top, and an ink replenishing port 19 is provided in a part thereof. The ink replenishing port 19 has an inner diameter A smaller than the outer diameter B of the bead 8. Thus, by making the inner diameter A of the ink replenishing port 19 smaller than the outer diameter B of the bead 8, it is possible to prevent the beads 8 from being discharged from the ink replenishing port 19. Accordingly, the ink tank 14 can be circulated in a state where the beads 8 are accommodated in the tank body 17.

  The tank main body 27 shown in FIG. 5 is covered with a casing at the top, and a cylindrical ink replenishing port 29 is provided at a part thereof. The ink replenishing port 29 has an inner diameter larger than the outer diameter of the bead 8. A lid 31 that is attached to and detached from the ink supplement port 29 is attached to the ink supplement port 29. A mesh-shaped inner lid 32 is attached to the ink replenishing port 29. The stitch of the inner lid 32 is formed smaller than the outer diameter of the bead 8. When the ink 6 is replenished, the lid 31 is removed and the ink 6 is replenished from the ink replenishing port 29. When the replenishment of the ink 6 is completed, the lid 31 is attached and the ink replenishing port 29 is closed. Thus, by providing the lid 31, when the ink 6 is not replenished, the tank body 27 can be sealed by the lid 31, so that air flowing into the tank body 27 can be blocked. it can. Further, by providing the inner lid 32 of the stitch smaller than the outer diameter of the bead 8, it is possible to prevent the bead 8 from being discharged from the ink replenishing port 29 regardless of the inner diameter of the ink replenishing port 29. Thereby, the ink tank 14 can be circulated in a state where the beads 8 are accommodated in the tank body 27. The inner lid 32 may be attached to the ink replenishing port 29 or may be attached to the tank body 27.

FIG. 1 is a diagram illustrating a configuration of a bulk ink supply system including an ink tank according to the present embodiment. It is sectional drawing of the ink tank shown in FIG. It is a figure which shows the measurement result of the dissolved oxygen amount of an ink. It is sectional drawing of another ink tank. It is sectional drawing of another ink tank.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Bulk ink supply system, 2 ... Carriage, 3 ... Inkjet head, 4, 14, 24 ... Ink tank, 5 ... Pipe, 6 ... Ink, 7, 17, 27 ... Tank main body, 8 ... Bead, 9, 19, 29 ... Ink replenishing port, 10 ... Supply port, 31 ... Lid, 32 ... Inner lid.

Claims (4)

A non-sealed ink tank used for a bulk ink supply system for supplying ink to an ink jet head of an ink jet printer and storing the ink supplied to the ink jet head,
A tank body in which ink is stored;
A solid air shield housed in the tank body and having a specific gravity smaller than that of the ink;
An ink tank comprising:   2. The ink tank according to claim 1, wherein the tank main body contains a number of the solid air shields covering a surface of the ink stored in the tank main body. The tank body is formed with a supply port for supplying the ink to the inkjet head,
The ink tank according to claim 1, wherein the solid air shield is formed with an outer diameter larger than an inner diameter of the supply port. An ink storage method that is used in a bulk ink supply system that supplies ink to an ink jet head of an ink jet printer and stores the ink supplied to the ink jet head in a non-sealed ink tank,
A method of storing ink, wherein the ink is stored in the tank body in a state where a solid air shield having a specific gravity smaller than that of the ink is accommodated in the tank body storing the ink.

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