TW201725127A - Ink circulation method and apparatus capable of keeping a stable ink flow between the ink jet head and two ink cartridges, and preventing improper ink leakage from the ink jet head - Google Patents

Abstract

The present invention relates to an ink circulation method and apparatus comprising a first flow path provided between a first ink cartridge and a second ink cartridge, the second ink cartridge being connected to a negative pressure source, causing the ink transported from the first ink cartridge to the second ink cartridge; a second flow path provided between the second ink cartridge and an ink jet head, the ink flowing down the second flow path to the ink jet head; and a third flow path provided between the ink jet head and the first ink cartridge, and the third flow path provided with a return ink pump for transporting the ink from the ink jet head back to the second ink cartridge.

Description

Ink circulation method and device

The present invention relates to a recycling method and apparatus, and more particularly to an ink circulation method and apparatus for maintaining ink flow between a printing head and an ink cartridge in a printing apparatus for ink-jet printing a substrate.

The ink composition of the conventional inkjet printing is formed by mixing the pigments into a solvent, but the pigment and the solvent have different characteristics, and the ink after the blending is caused by factors such as an increase in the placement time or the gradual evaporation of the solvent. The formation of a precipitate to cause stratification of the ink; Patent No. I248878 "Inkjet Printing" discloses a printer and an inkjet printing method which utilizes an ink feed pump to transport ink from a first storage tank to a second The sump further transports the ink of the second storage tank through the printing head to the first storage tank by the difference in ink height between the filling pump and the second storage tank and the first storage tank, and avoids the ink feeding pressure generated by the action of the siphon tube. The ink of the print head leaks improperly from the nozzle to establish circulation of the ink through the entire system, and keep the solid in the ink in a suspended state, and helps to maintain the suspension state by the action of the pusher and the coaxial static mixer. .

The conventional ink circulation system uses a pump as a power source for conveying the flow between the respective storage tanks and the printing head, but when the pump conveys the ink, bubbles are easily generated, and when the ink having the bubbles enters the printing head, it is possible to print. It will cause the size of the ejected ink droplets to be uneven, the flight path of the ink droplets to change, or the ink droplets to be ejected at all; in addition, only the ink generated by the action of the siphon tube is fed with pressure to prevent the ink of the printing head from leaking from the nozzle improperly. If there is a low-viscosity ink, there is still some doubt that the ink leaks and drops.

Accordingly, an object of the present invention is to provide an ink circulation method which is less likely to generate bubbles and which is less likely to leak ink from the ink jet head.

Another object of the present invention is to provide an ink circulation device which is less likely to generate bubbles and which is less likely to leak ink from the ink jet head.

The ink circulation method according to the object of the present invention comprises: an ink supply step of: forming a negative pressure inside a second ink storage cartridge, so that the ink in a first ink cartridge is attracted by the negative pressure in the second ink cartridge; Transmitting to the second ink cartridge via a first flow path, and causing the ink to flow through a second flow path to a height in an inkjet head below the second ink cartridge due to gravity; an ink returning step: The ink in the inkjet head is withdrawn through an ink returning pump on a third flow path and transported back into the first ink cartridge via the third flow path.

An ink circulation device according to another object of the present invention, comprising: means for performing the ink circulation method according to any one of claims 1 to 3.

Another ink circulation device according to another object of the present invention comprises: a first flow path disposed between a first ink cartridge and a second ink cartridge, wherein the second ink cartridge is connected to a negative pressure source to enable ink The liquid is transported from the first ink cartridge to the second ink cartridge; a second flow path is disposed between the second ink cartridge and an inkjet head, and the ink flows from the second flow path to the inkjet head a third flow path is disposed between the inkjet head and the first ink cartridge, and an ink return pump is disposed on the third flow path to transport ink back to the second ink cartridge by the inkjet head.

The ink circulation method and device of the embodiment of the invention firstly forms a negative pressure vacuum inside the second ink storage cartridge, and conveys the ink from the first storage cartridge to the second storage cartridge by suction in a negative pressure manner, thereby reducing the conventional pump. When the ink is conveyed, it is easy to generate bubbles for the ink; and when the ink flows into the inkjet head due to gravity, the suction of the negative pressure can keep the ink maintained at the bottom of the inkjet head without being inked. The head leaks down; and the ink is pumped back to the first ink storage cartridge by the ink returning pump to quantitatively limit the ink circulation flow, and the first ink cartridge is connected to the outside air through the vent hole. When the ink returns to the first ink storage cartridge, even if bubbles are generated, the air bubbles can be dissipated into the atmosphere, and the bubbles are not circulated into the inkjet head; in addition, the ink is filtered through the filter on the first flow path to the second The ink cartridge can filter the impurities in the ink to prolong the use time of the inkjet head, and the filter on the third flow path can also filter the impurities in the ink to prolong the use time of the ink return pump, and the check valve is set at Between the filter and the second ink cartridge, so When the cleaning step, will not be returned to the ink and impurities from the filter allows the flow of the filter in the case of the first flow path.

Referring to FIG. 1 , an ink circulation method according to a first embodiment of the present invention can be exemplified by the ink circulation device shown in the drawing, comprising: a first flow path 1 disposed on a first ink cartridge T1 and a second Between the ink cartridges T2, the first flow path 1 is provided with a solenoid valve 11, a filter 12 and a check valve 13, and the solenoid valve 11 is disposed between the filter 12 and the first ink cartridge T1. The check valve 13 is disposed between the filter 12 and the second ink cartridge T2; the first flow path 1 has an extension tube 14 extending into the first ink cartridge T1 and contacting the ink I under the liquid I surface. The other end has an extension tube 15 extending into the first ink cartridge T1 above the liquid level I of the ink I is not in contact with the ink I; the first ink cartridge T1 is provided with a vent hole T11 to make the interior of the first ink cartridge T1 and the outside air The second ink cartridge T2 is connected to a negative pressure source A1 and a positive pressure source A2, respectively, and is switched to use a negative pressure or a positive pressure state in the inner space of the second ink cartridge T2, and a liquid level is arranged on the second ink cartridge T2. The detecting sensor T21 is configured to detect the liquid level of the ink I to provide a judgment basis for opening or closing the electromagnetic valve 11; the first ink cartridge The position of T1 is higher than that of the second ink tank T2, and the ink I is supplied from the first ink tank T1 to the second ink tank T2 via the first flow path 1; a second flow path 2 is disposed in the second ink tank T2 and Between an inkjet head H, the inkjet head H is disposed at a lower position than the second ink cartridge T2, and the ink I is supplied from the second ink cartridge T2 to the inkjet head H via the second flow path 2; The flow path 3 is disposed between the inkjet head H and the first ink cartridge T1. The third flow path 3 is provided with an ink return pump 31 and a filter 32. The ink return pump 31 is disposed on the first ink cartridge T1. Between the filter 32 and the filter 32, the filter 32 is disposed between the ink returning pump 31 and the inkjet head H, and the ink I is returned from the inkjet head H to the first ink cartridge T1 via the third flow path 3; The road 3 has an extension pipe 33 extending into the first ink tank T1 and above the liquid level I of the ink I is not in contact with the ink I; a controller C, the electrical connection solenoid valve 11, the negative pressure source A1, the positive pressure source A2 The liquid level detecting sensor T21 and the ink returning pump 31 control the opening and closing of the electromagnetic valve 11, the negative pressure source A1, the positive pressure source A2 and the ink returning pump 31 according to preset values.

Referring to FIG. 1 and FIG. 2, the ink circulation method according to the first embodiment of the present invention includes: an ink supply step S1: opening the negative pressure source A1 and forming a negative pressure vacuum inside the second ink storage cartridge T2, so that The ink I in the ink tank T1 is sucked by the negative pressure in the second ink tank T2, passes through the first flow path 1 and passes through the opened electromagnetic valve 11 and is filtered by the filter 12 and then sent to the first through the check valve 13. In the second ink cartridge T2, the ink I in the second ink cartridge T2 is subjected to gravity by the second flow path 2 and then flows down to the ink head H located below the height, because P=ρgh, at ρ In the case where (liquid density) and g (gravitational acceleration) are fixed, h (liquid height) is changed by adjusting P (pressure), and this h is set to detect the liquid level from the bottom of the inkjet head H to the second ink tank T2. The distance d between the position of the sensor T21 is such that the ink I in the inkjet head H is attracted by the negative pressure and remains at the bottom of the inkjet head H without leaking under the negative pressure state in the second ink cartridge T2. When the liquid level detecting sensor T21 of the second ink tank T2 detects the ink I, it indicates that the liquid level reaches the preset height, that is, the solenoid valve 11 is closed. Dissolving the supply of the ink I of the second ink cartridge T2, and vice versa, opening the solenoid valve 11; a cleaning step (Sur): after the inkjet head H is replaced or reassembled, the cleaning step S2 is performed. The ink I is sufficiently filled in all the pipes (not shown) in the inkjet head H. When the cleaning step S2 is performed, the negative pressure source A1 is turned off and the positive pressure source A2 is turned on to form a positive inside the second ink cartridge T2. The ink I is discharged from the second ink tank T2, and the check valve 13 on the first flow path 1 prevents the ink I remaining in the first flow path 1 from being sent back to the filter 12 by the positive pressure air flow. The ink returning pump 31 on the third flow path 3 is also in a closed state, so that the ink I is ejected from the second ink cartridge T2 to the inkjet head H and by the nozzle (not shown) of the inkjet head H along the pressure. After setting the time, the positive pressure source A2 is turned off and the negative pressure source A1 is turned on again; wherein the cleaning step S2 is not a formal printing inkjet, and the official printing inkjet system is piezoelectrically ejecting the ink I (piezoelectric method is not The feature of the present invention is not described in detail here; an ink returning step S3: opening the ink returning pump 31 on the third flow path 3, and the ink I in the ink jet head H And discharged through the third flow path 3 by the filter 32 and then returned to the first ink tank T1 via the ink return pump 31; wherein, if the ink jet head H is not replaced or reassembled, or the cleaning step has been performed S2, the ink supply step S1 and the ink returning step S3 are repeated to keep the ink I circulating in the first ink tank T1, the second ink tank T2, and the ink jet head H, and the negative needs to be turned off except when the cleaning step S2 is performed. The pressure source A1 and the ink return pump 31 maintain the ink source I circulating, and the negative pressure source A1 and the ink return pump 31 are kept in an open state, and the ink return pump 31 is preset according to a preset time. The ink I is intermittently conveyed back to the first ink tank T1.

Referring to FIG. 3, in the second embodiment of the present invention, the first ink cartridge T1' needs to be disposed at a higher height, so the space, weight, etc. of the first ink cartridge T1' will be limited, and the capacity cannot be set. In the ink cartridge, the ink circulation device according to the second embodiment of the present invention, based on the structure of the first embodiment, further includes: a fourth flow path 4' disposed in the first ink cartridge T1' and a first Between the three storage ink cartridges T3', the fourth flow path 4' is provided with a filling pump 41', and the first ink storage cartridge T1' is provided with a liquid level detecting sensor T11' for detecting the liquid level of the ink I. In order to provide a basis for determining whether the filling pump 41' is opened or closed; wherein the capacity of the third ink cartridge T3' is greater than the first ink cartridge T1' or the second ink cartridge T2', the position of the first ink cartridge T1' is set high. In the second ink cartridge T2', the inkjet head H' is disposed lower than the second ink cartridge T2' and higher than the third ink cartridge T3'.

Referring to Figures 3 and 4, the ink circulation method of the second embodiment of the present invention is implemented, except for the ink supply step S1', the cleaning step S2', and the ink returning step S3' which are the same as the first embodiment. : an ink filling step S4': when the liquid level detecting sensor T11' on the first ink tank T1' does not detect the ink I, the filling pump 41' is turned on to cause the ink I to be transported by the third ink tank T3' Until the first ink cartridge T1' is detected, until the liquid level detecting sensor T11' detects the ink I, that is, the filling pump 41' is turned off, and if the ink I is not detected again, the filling pump 41' is turned on again to maintain the The ink of the ink tank T1' is at a preset height.

In the ink circulation method and device according to the embodiment of the present invention, a negative vacuum is formed inside the second ink cartridge T2, and the ink I is transported from the first ink cartridge T1 to the second ink cartridge T2 by suction in a negative pressure manner, thereby reducing The conventional pump is easy to generate bubbles in the ink I when the ink is conveyed; and when the ink I flows into the inkjet head H due to gravity, the ink can be kept in the spray due to the suction of the negative pressure. The bottom of the ink head H is not leaked by the inkjet head H; and the ink I is sucked back from the inkjet head H to the first ink tank T1 by the ink return pump 31, and the circulation flow rate of the ink I can be kept stable. And because the first ink cartridge T1 communicates with the outside atmosphere through the vent hole T11, when the ink I returns to the first ink cartridge T1, even if bubbles are generated, the bubbles can be dissipated into the atmosphere, and the bubbles are not circulated. Inkjet head H; further, the ink I is filtered on the first flow path 1 through the filter 12 to the second ink cartridge T2, and the impurities in the ink I can be filtered to extend the use time of the inkjet head H, and the third flow The filter 32 on the road 3 can also filter the impurities in the ink I to extend the use time of the ink return pump 31, and the check valve 13 is provided at Between the filter 32 and the second tank cartridge T2, so the washing step is performed at S2, the ink I does not have to reflux and the impurity filter 32 from the filter 32 in the case of a flow in the first flow path.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

1‧‧‧First flow path
11‧‧‧ solenoid valve
12‧‧‧Filter
13‧‧‧Check valve
14‧‧‧ Extension tube
15‧‧‧ Extension tube
2‧‧‧Second flow path
3‧‧‧ third flow path
31‧‧‧Ink pump
32‧‧‧Filter
33‧‧‧ Extension tube
4'‧‧‧ fourth flow path
41'‧‧‧ Filling pump
A1‧‧‧ Negative pressure source
A2‧‧‧ positive pressure source
C‧‧‧ controller
D‧‧‧distance
H‧‧‧Inkjet head
H'‧‧‧Inkjet head
I‧‧‧ ink
S1‧‧‧Ink supply step
S2‧‧‧ cleaning steps
S3‧‧‧Returning step
S1'‧‧‧Ink supply step
S2'‧‧‧ cleaning steps
S3'‧‧‧Return to ink step
S4'‧‧‧ ink filling step
T1‧‧‧first ink cartridge
T11‧‧‧ vents
T2‧‧‧Second ink cartridge
T21‧‧‧ liquid level detection sensor
T1'‧‧‧first ink cartridge
T11'‧‧‧ liquid level detection sensor
T2'‧‧‧Second ink cartridge
T3'‧‧‧third storage cartridge

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing an ink circulation device of a first embodiment of the present invention. Fig. 2 is a flow chart showing the steps of the ink circulation in the first embodiment of the present invention. Fig. 3 is a schematic view showing an ink circulation device of a second embodiment of the present invention. Fig. 4 is a flow chart showing the ink circulation step of the second embodiment of the present invention.

1‧‧‧First flow path

11‧‧‧ solenoid valve

12‧‧‧Filter

13‧‧‧Check valve

14‧‧‧ Extension tube

15‧‧‧ Extension tube

2‧‧‧Second flow path

3‧‧‧ third flow path

31‧‧‧Ink pump

32‧‧‧Filter

33‧‧‧ Extension tube

A1‧‧‧ Negative pressure source

A2‧‧‧ positive pressure source

C‧‧‧ controller

D‧‧‧distance

H‧‧‧Inkjet head

I‧‧‧ ink

T1‧‧‧first ink cartridge

T11‧‧‧ vents

T2‧‧‧Second ink cartridge

T21‧‧‧ liquid level detection sensor

Claims (11)

An ink circulation method comprising: an ink supply step of: forming a negative pressure inside a second ink storage cartridge, so that ink in a first ink cartridge is attracted by a negative pressure in the second ink cartridge, via a first flow The ink is conveyed into the second ink cartridge, and the ink flows through a second flow path to a height of one of the inkjet heads under the second ink cartridge due to gravity; an ink returning step: by a first An ink returning pump is provided on one of the three flow paths, and the ink in the ink jet head is drawn out and transported back to the first ink cartridge via the third flow path. The ink circulation method according to claim 1, wherein the ink is transported to the second ink cartridge through a solenoid valve on the first flow path and filtered by a filter and then passed through a check valve. . The ink circulation method according to claim 1, wherein the ink is filtered by the filter on the third flow path and then returned to the first ink tank by an ink pump. An ink circulation device comprising: means for performing the ink circulation method according to any one of claims 1 to 3. An ink circulation device comprising: a first flow path disposed between a first ink cartridge and a second ink cartridge, the second ink cartridge being connected to a negative pressure source for conveying ink from the first ink cartridge To the second ink cartridge; a second flow path is disposed between the second ink cartridge and an inkjet head, the ink flows down from the second flow path to the inkjet head; a third flow path is provided Between the inkjet head and the first ink cartridge, an ink return pump is disposed on the third flow path to transport ink back to the second ink cartridge by the inkjet head. The ink circulation device of claim 5, wherein the first ink cartridge is disposed at a higher position than the second ink cartridge, and the inkjet head is disposed at a lower position than the second ink cartridge; The first ink cartridge is provided with a vent hole. The ink circulation device of claim 5, wherein the first flow path is provided with a solenoid valve, a filter and a check valve, and the electromagnetic valve is disposed between the filter and the first ink cartridge. The check valve is disposed between the filter and the second ink cartridge; the second ink cartridge is provided with a liquid level detecting sensor for providing a judgment basis for opening or closing the electromagnetic valve. The ink circulation device of claim 5, wherein the third flow path is provided with a filter disposed between the ink return pump and the ink jet head. The ink circulation device of claim 5, wherein the second ink cartridge is connected to a positive pressure source and is switched to be used with the negative pressure source. The ink circulation device of claim 5, wherein a fourth flow path is disposed between the first ink cartridge and a third ink cartridge, and a filling pump is disposed thereon to enable ink from the third The ink cartridge is transported to the first ink cartridge; the first ink cartridge is provided with a liquid level detecting sensor for providing a basis for determining whether the filling pump is turned on or off. The ink circulation device of claim 10, wherein the first ink cartridge is disposed at a higher position than the second ink cartridge, and the inkjet head is disposed at a lower position than the second ink cartridge. The third ink cartridge is provided; the first ink cartridge is provided with a vent hole.