JP2006231809A - Ink deaerator for ink-jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink deaerator for an ink-jet printer, which is free from re-melting of air in deaerated ink, prevents the ink from thickening because no repeated deaerating operation is necessary, to thereby achieve stable ejection operation of an ink-jet print head. <P>SOLUTION: According to the structure of the deaerator for the ink-jet printer, an ink container to be arranged in a vacuum container is flexibly deformable according to fluctuation of the ink, and has one end thereof openable. Further the deaerator is formed of a material of low gas permeability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink deaeration device used in an ink jet printer that ejects ink droplets to record an image on a recording medium.

  It is known that the presence of dissolved air in ink used in an ink jet printer has a great influence on printing performance, and it is very important to reduce the dissolved air, that is, deaeration of the ink. As a method usually used as a countermeasure, an ink 42 that has been previously degassed in a hermetically sealed ink pack 41 made of a film with low gas permeability as shown in FIGS. An injected ink cartridge is being used.

  In some cases, a deaerator as shown in FIG. 5 is installed in the vicinity of a printer (not shown) to use deaerated ink. An ink container 28 having no upper container wall is installed in the vacuum container 24, and a vacuum valve 26 and an ink container 28 provided between a vacuum pump (not shown) for evacuating the inside of the vacuum container 24, An ink injection valve 44 for controlling the injection of the ink 27 provided between the main ink tank (not shown) and the ink 27 for controlling the liquid feeding to the ink jet head (not shown). The ink filling valve 23 and the air leak valve 25 for opening and closing the inside of the vacuum container 17 with respect to the atmosphere are configured.

  First, the ink injection valve 44 is opened while the vacuum valve 26 is closed, the air leak valve 25 is opened, and the ink filling valve 23 is closed, and the ink 27 is put into the ink container 28 until a predetermined ink amount is reached. The injection valve 44 is closed. Subsequently, the air leak valve 25 is closed, the vacuum valve 26 is opened, the air in the vacuum vessel 24 is exhausted, and deaeration is performed until a predetermined degree of vacuum is reached. After the deaeration, the vacuum valve 26 is closed, the air leak valve 25 is opened, the inside of the vacuum container 24 is opened to the atmosphere, the ink filling valve 23 is opened, and the ink is sent to the ink jet head. In this case, the reason for opening the air leak valve 25 and returning the inside of the vacuum container 24 to the atmospheric state is that if the ink 27 is in a vacuum state, the ink 27 is more pressure than the inkjet head even if the ink filling valve 23 is opened. This is because the ink cannot be filled. Further, when the ink in the ink container 27 is reduced by printing, the ink is injected again and the above deaeration procedure is repeated.

In the above description, the case where the ink color is one is described. However, when there are a plurality of inks, it is necessary to arrange a plurality of deaeration devices in FIG. 5 by the number of ink colors. As a countermeasure, there is an apparatus in which ink containers 21 and 22 are placed in a vacuum container 17 as shown in FIG. 6 and a plurality of colors of ink are deaerated by a deaeration procedure similar to that shown in FIG.
JP 2003-282246 A

  When an ink cartridge using the ink pack 41 as described above is used, degassed ink is used, so that the desired printing performance can be obtained, but since it is necessary to fill a small amount of ink cartridges, the cartridge manufacturing cost is reduced. That is, the running cost when using the printer is very high.

  In addition, when a deaeration device installed near the printer as described above is used, deaeration is sufficient immediately after the completion of deaeration, so that desired printing performance can be obtained, but ink is applied to the inkjet head after deaeration. When filling, it is necessary to set the inside of the vacuum container 24 to atmospheric pressure, so that the air is re-dissolved in the ink 27 that has been degassed once, and the ejection performance of the ink jet deteriorates. As a countermeasure, it is possible to return the dissolved air amount of the ink 27 to a desired value by degassing the ink that has been redissolved. However, by repeating the degassing operation, the solvent of the ink As a result, the ink 27 thickens and the ejection performance changes. Further, when the ink color increases, the vacuum container 24 is required by the number of ink colors, so that the entire deaeration device becomes very large and the cost is high.

  When a plurality of ink containers shown in FIG. 6 are put in one vacuum container, only one vacuum container 17 is required, so the deaeration device itself can be made small, but the amount of ink used is different for each color. The difference in the remaining amount of ink can be made, the ink that runs out of ink at the beginning, and the ink that needs to be degassed again can be degassed as desired, but the ink that uses less ink has been degassed Since the deaeration was performed several times, the viscosity was greatly increased and the discharge performance was changed.

  Therefore, the present invention does not require an ink cartridge, and when filling the ink jet head with ink, there is no need to return the inside of the vacuum container to the atmosphere. In addition, during the deaeration of other inks, it can be blocked from the atmosphere in the vacuum container, so that thickening can be prevented, so that the proper viscosity can be maintained in a stable deaeration state at all times. The object is to provide a deaeration device.

  In the degassing apparatus of the present invention, an ink container placed in a vacuum container has a structure in which one end can be opened and closed, can be flexibly deformed by increasing or decreasing ink, and is formed of a material having low gas permeability. In the air, open and close the ink container to discharge the dissolved air contained in the ink.After deaeration for a predetermined time, close the opening and fill the ink jet head with ink without leaving the vacuum container in the atmosphere. By doing so, air can be prevented from redissolving in the ink that has been once degassed, and since it is not redissolved, there is no need for a degassing operation again, thus preventing thickening.

  In addition, when using a plurality of inks, a plurality of flexible ink containers are placed in a single vacuum container, and the amount of ink used varies depending on the color, and the remaining amount of ink is different. If the air cannot be taken, the opening of the ink container that is not deaerated is not opened, so that thickening can be prevented.

  As described above, the deaeration device of the present invention does not require an ink cartridge into which the pre-deaerated ink 42 has been injected, and therefore does not require the cartridge manufacturing cost, so it is inexpensive, that is, the running cost when using the printer is low. Very low.

  Ink head can be filled with ink while the ink container is shut off from the atmosphere outside the container after the deaeration operation is completed, so that re-dissolution of air into the ink can be prevented and there is no re-dissolution of air. Therefore, it is not necessary to deaerate again, and it is possible to prevent the ink from thickening, so that stable ink jet print head ejection can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating a basic configuration of a deaeration device for an ink jet printer according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a vacuum container that forms a decompressed state necessary for degassing ink, and a vacuum pump 46 for decompressing the inside of the vacuum container 1 is connected thereto. A vacuum valve 4 for controlling the pressure in the vacuum vessel 1 is installed between the vacuum vessel 1 and the vacuum pump 46, and an air leak valve 39 for returning the inside of the vacuum vessel 1 from a vacuum state to an atmospheric pressure state. Is attached. 45 is a pressure fine adjustment valve which can be opened and closed in order to keep the pressure value measured by the vacuum gauge 51 at a desired pressure.

  2a and 2b are ink containers formed of a film material having a thickness of about 0.2 mm obtained by vacuum deposition of an aluminum material, and can be easily deformed by increasing or decreasing the ink. Thereby, a flexible ink container with low gas permeability can be realized. The ink container 2 a and the main ink tank 49 are connected via a piping tube, and the ink injection valve 3 for controlling ink injection is installed between the ink container 2 a and the main tank 49. The ink container 2 b and the main ink tank 50 are connected via a piping tube, and an ink injection valve 7 for controlling ink injection is installed between the ink container 2 b and the main tank 50. Further, an ink container opening / closing valve 5 is installed at the upper part of the ink container 2a, and the ink in the ink container 2a is opened during the deaeration operation and closed after the deaeration operation. An ink filling valve 9 for controlling ink conveyance to the inkjet head 47 is provided. An ink container opening / closing valve 6 is installed at the upper part of the ink container 2b, and the ink in the ink container 2b is opened during the deaeration operation and closed after the deaeration operation. An ink filling valve 8 for controlling the ink conveyance to 48 is installed. Sub tanks 52 and 53 are connected between the ink containers 2a and 2b and the ink jet heads 47 and 48, respectively, and have a function of absorbing pressure changes in the ink containers 2a and 2b and a head value management function for the heads. is doing.

  Next, a procedure for actually degassing ink and filling the ink jet head with ink will be described. First, the air leak valve 39 is closed, the ink injection valves 3 and 7 are closed, the ink filling valves 8 and 9 are closed, the ink container opening and closing valves 5 and 6 are opened, the vacuum valve 4 is opened, and the vacuum pump 46 is turned on. The vacuum vessel 1 is evacuated and the pressure fine adjustment valve is adjusted so that the vacuum gauge 51 becomes constant at 15 Pa. After confirming that the vacuum gauge 51 is stable, the ink injection valves 3 and 7 are opened to inject ink into the ink containers 2a and 2b, respectively. In the present invention, in order to avoid sudden boiling, ink was injected at a rate of 10 cc / min, and an ink amount of 100 cc was injected into the ink containers 2a and 2b for 10 minutes. FIG. 2 shows a state of the ink container 2a before the ink is injected (left figure) and a state of the ink container 2a after the ink injection (right figure). By injecting the ink into the ink container 2a, FIG. It has a bulging structure. In the present invention, the ink injection speed is set to 10 cc / min. However, it is necessary to increase or decrease the ink injection speed to an appropriate injection speed depending on the foaming property of the ink, and the degree of vacuum is constant at 15 Pa. Although the degree of vacuum was adjusted, it is necessary to adjust the pressure to an appropriate degassing pressure depending on the type of ink. After the above 10 minutes of ink injection, the ink is left at a pressure of 15 Pa for another 10 minutes until the dissolved air is discharged to a desired deaeration level, and the deaeration is completed. Since the ink container open / close valves 5 and 6 are closed after the deaeration, it is necessary to avoid exposing to an excessive vacuum state in order to prevent thickening. The ink filling valve 9 is opened to transport the sub tank 52 ink. After the desired amount of ink is filled in the sub tank 52, ink is filled into the inkjet head 47 by a head maintenance unit (not shown) that maintains the inkjet head 47. Similarly, the ink filling valve 8 is opened to transport the sub tank 53 ink. After the sub-tank 53 is filled with a desired amount of ink, ink is filled into the ink-jet head 48 by a head maintenance unit (not shown) for maintaining the ink-jet head 48 so that each ink-jet 47 and 48 can be printed. To do.

  Next, the operation of the deaeration device of the present invention while the printer is driven will be described. When the ink is consumed by operating the ink jet heads 47 and 48, the ink container is flexible, so that the pressure can be kept constant by contracting the ink container by the amount of ink reduction. The pressure fluctuations can be prevented from being transmitted to the ink jet heads 52 and 53 and the ink jet heads 47 and 48, that is, stable printing can be performed without affecting the printing operation. Further, during printing, since the pressure in the vacuum container 1 can be cut off, it is not exposed to a vacuum atmosphere that is degassed for a long time, so that thickening can be prevented. Furthermore, the case where the ink jet 47 prints a larger amount than the ink jet head 48, consumes more ink, and first the ink container 2a is empty will be described. After the ink filling valve 9 is closed and the ink container opening / closing valve 5 is opened, the ink injection valve 3 is opened, and ink is injected at a speed of 10 cc / min. Inject until 2a is satisfied. In this case, only the ink container 2a can be deaerated without affecting the ink container 2b.

  Furthermore, the mechanism for controlling the injection of ink into the ink container and the mechanism for filling the ink in the ink container into the ink jet head shown in FIG. The case where the tube pump which conveys is used is demonstrated. In general, the tube pump can transport the liquid passed through the tube during rotation, and has a stop valve function since the roller is stopped while pressing the tube during the stop. In the embodiment shown in FIG. 1 described above, since the ink was transported by opening and closing the valve, a liquid feed pump such as a butterfly pump was sometimes required. By using the tube pumps 29 and 30 as the ink filling valve, it is possible to easily realize the functions of the ink transfer and the ink stop valve with a single component.

  Next, a case where a plurality of ink containers 2a and 2b are arranged in parallel for one ink color as shown in FIG. 4 will be described. In FIG. 1, since one ink container is arranged for each main tank, when the ink consumption is very large, there is a case where the ink transported to the inkjet head is insufficient and the printing operation is stopped. Since a plurality of inks are arranged and ink can be conveyed alternately, there is no shortage of ink during deaeration, and the printer can be operated more continuously.

  As described above, the ink container placed in the vacuum container has a structure that can be opened and closed at one end, can be flexibly deformed by increasing or decreasing the ink, and is formed of a material having low gas permeability. Since there is no need to open the atmosphere when filling the head with ink or during printing operation, air can be prevented from redissolving once degassed. Since thickening can be prevented, stable ink jet head ejection can be realized.

The figure which shows typically the basic composition which concerns on the deaeration apparatus for inkjet printers concerning embodiment of this invention. The figure which shows typically the basic operation | movement of the ink container which concerns on embodiment of this invention. The figure which shows typically the structure at the time of using a tube pump for the ink conveyance which concerns on the deaeration apparatus for inkjet printers concerning embodiment of this invention. The figure which shows typically about the structure which uses two ink containers with respect to the ink of 1 color which concerns on the deaeration apparatus for inkjet printers concerning embodiment of this invention. The figure which shows typically the basic composition which concerns on the conventional deaeration apparatus for inkjet printers The figure which shows typically the basic composition which concerns on the conventional deaeration apparatus for inkjet printers Schematic diagram of a conventional ink cartridge

Explanation of symbols

1 Vacuum container 2a, 2b Ink container 3, 7 Ink injection valve 4 Vacuum valve 5, 6 Ink container opening / closing valve 8, 9 Ink filling valve 39 Air leak valve 29, 30, 31, 32 Tube pump 41 Ink pack 42, 43 Ink 47, 48 Inkjet head 49, 50 Main ink tank 51 Vacuum gauge 52, 53 Sub tank

Claims (8)

A vacuum container that can be depressurized to the degree of vacuum necessary to degas the ink;
An ink deaeration device for an ink jet printer, comprising: an ink container installed in the vacuum container, wherein the ink container has a structure that can be flexibly deformed by increasing or decreasing ink and having one end openable and closable. 2. The ink deaerator for an ink jet printer according to claim 1, wherein the ink container is formed of a film-like material. The ink deaerator for an ink jet printer according to claim 1, wherein the ink container is formed of a material having low gas permeability. The ink degassing device for an ink jet printer according to claim 1, wherein a plurality of the ink containers are arranged in the vacuum container. 2. The ink deaerator for an ink jet printer according to claim 1, wherein a mechanism for controlling the injection of ink into the ink container is provided outside the vacuum container. 2. The ink deaerator for an ink jet printer according to claim 1, wherein a mechanism for filling the ink jet head with ink in the ink container is provided outside the vacuum container. 6. The ink removing device for an ink jet printer according to claim 5, wherein the mechanism for controlling the injection of the ink into the ink container is a tube pump that conveys ink by pressing an elastic tube while rotating a roller. Qi device. 7. The ink jet printer according to claim 6, wherein the mechanism for filling the ink jet head with ink in the ink container is a tube pump that presses an elastic tube while rotating a roller to convey ink. Ink degassing device.

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