The present disclosure relates to a recording apparatus that records an image, and a recording head.
There is known an inkjet printer (inkjet recording apparatus) that includes an ink tank capable of storing ink to be supplied to a recording head, which discharges the ink. The ink is supplied from the ink tank to the recording head via an ink supply path. Japanese Patent Application Laid-Open No. 2017-81075 discusses a recording head that internally has an air layer between a liquid supply unit that is a path capable of distributing a liquid and a holding member that holds the liquid.
However, according to the configuration discussed in Japanese Patent Application Laid-Open No. 2017-81075, if the air in the air layer within the recording head expands due to a temperature change or an atmospheric pressure change, the surface of a liquid at an outlet of a supply port may move backward to let the air into the liquid flow path. Thus, cleaning or ink suction is sometimes necessary to expel the air from the liquid flow path.
Aspects of the present disclosure provide a recording apparatus that, if the air in a recording head expands due to a temperature change or an atmospheric pressure change, suppresses the air from entering into a supply path.
According to an aspect of the present disclosure, a recording apparatus includes a recording head configured to discharge a liquid and record an image, a first liquid reservoir unit configured to store the liquid to be supplied to the recording head, a liquid supply port configured to supply the liquid stored in the first liquid reservoir unit into the recording head, a liquid supply path connecting the first liquid reservoir unit and the liquid supply port, a second reservoir unit, disposed in the recording head, configured to reserve the liquid supplied from the liquid supply port, and a holding unit configured to hold the liquid supplied from the second reservoir unit, in the recording head, wherein the second reservoir unit includes an opening that is provided upward in a direction of a gravitational force with respect to the liquid supply port and is configured to supply the liquid to the holding unit, in a case where the recording head is in a posture of performing recording.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
First, an outline of an inkjet recording apparatus according to the present disclosure will be described.
The platen 101 is arranged at a position facing a recording head 13. The platen 101 supports a back side of the recording medium to maintain a constant or predetermined distance between an ink discharge portion 81 (see
The ejection roller 103 is a rubber roller having a large friction coefficient. The spur roller is elastically biased to the ejection roller 103 by a pressing unit such as a spring not illustrated.
The recording head 13 is mounted on a bottom of a carriage 30 to face the conveyed recording medium, and has the ink discharge portion 81 that discharges ink for each ink color. The carriage 30 is driven to reciprocate by a driving unit such as a motor in an X direction (main scanning direction) along a guide rail 104, which is arranged above and below. The X direction refers to a direction orthogonal to a conveyance direction (Y direction) of the recording medium on a horizontal plane.
The recording head 13 discharges ink droplets while moving together with the carriage 30 in the main scanning direction to record an image of one band on the recording medium on the platen 101. Once an image of one band is recorded, the recording medium is conveyed in a predetermined amount by the conveyance roller in the conveyance direction (intermittent conveyance operation). By repeating this one-band recording operation and the intermittent conveyance operation, a full image based on image data is recorded on the recording medium.
A plurality of independent ink tanks 15 is fixed to an apparatus body, as first liquid reservoir units corresponding to the colors of ink discharged from the recording head 13. The ink tanks 15 and the recording head 13 are connected via joints not illustrated by ink supply paths 14, which are liquid supply paths corresponding to the colors of ink. This allows the color ink stored in the ink tanks 15 to be individually supplied to the ink discharge portions 81 of the recording head 13 corresponding to the ink colors. In addition, a maintenance unit 40 described below (see
At the time of ink injection, the user removes the tank cap 22 and injects the ink from an ink injection container not illustrated into the corresponding ink tank 15 via the ink injection port 21. Each of the ink tanks 15 has an atmosphere communication part not illustrated, and the ink in the ink tank 15 communicates with the atmosphere via the atmosphere communication part.
The ink tanks 15 in the present exemplary embodiment are not limited to a type fixed to the apparatus body but can be of a cartridge type detachably attached to the apparatus body.
The cap part 301 is formed of a flexible material and is movable to a capping position where the ink discharge portion 81 of the recording head 13 is covered and a separated position where the ink discharge portion 81 is not covered. The cap part 301 is connected to the pump 303. When the pump 303 is driven by a pump motor not illustrated in a state where the cap part 301 is at the capping position, negative pressure is generated inside of the cap part 301 so that the ink is sucked from the recording head 13. The cap part 301 and the pump 303 are connected each other via a cap tube, and the ink sucked from the recording head 13 by an ink suction operation is collected into a waste ink tank not illustrated.
The case 82 is provided with the ink discharge portion 81 having a plurality of discharge ports (see
The ink holding member 84 and the filter 83 are desirably kept in a state of being pressed in contact with each other within the case 82. For this end, the pressing rib 72 is arranged on a back side of the lid member 70 to press the ink holding member 84 in a direction toward the filter 83. The lid member 70 is welded and attached to the case 82 in a state where the filter 83 and the ink holding member 84 are housed in the case 82. At this time, the pressing rib 72 presses the ink holding member 84. Accordingly, the ink holding member 84 and the filter 83 are pressed in contact with each other.
The ink discharge portion 81 of the recording head 13 is arranged at a position higher than a gas-liquid exchange portion where the ink reserved in the ink tank 15 and the atmosphere face each other, as seen in the Z direction. Accordingly, the negative pressure is generated in the ink discharge portion 81 due to a water head difference, which is a difference in height from the gas-liquid exchange portion in the ink tank 15. By the negative pressure, the ink is held in the ink discharge portion 81 and is suppressed from leaking out of the ink discharge portion 81. The present disclosure is not limited to the configuration of the recording head 13 and the ink tanks 15 using a water head difference but is also applicable to a configuration in which a negative pressure generation mechanism is provided in the ink tank 15.
The ink buffer 90 is placed in a space between the ink supply port 71 and a top surface of the ink holding member 84 regulated in position by the pressing rib 72. In the present exemplary embodiment, the ink buffer 90 is provided in the form of a container arranged immediately under the ink supply port 71 to temporarily reserve the ink supplied from the ink supply port 71. The ink buffer 90 has an opening 91 at a side surface portion, so that the ink having supplied from the ink supply port 71 and temporarily reserved is supplied to the ink holding member 84 through the opening 91. The opening 91 is formed at a position higher than a lower end of the ink supply port 71 as seen in the Z direction.
At the time of initial filling of ink into the recording head 13, the ink discharge portion 81 is sealed with the cap part 301 arranged in the maintenance unit 40. Thereafter, the ink is sucked by the pump 303 connected to the cap part 301 so that the negative pressure is generated inside of the cap part 301. As the sucking by the pump 303 is continuously repeated, the inside of the ink supply path 14 filled with the air before the initial filling will be filled with the ink up to the ink supply port 71.
Even in a state before the initial filling, the recording head 13 may hold a larger amount of ink than the volume of the ink supply path 14. In such a case, the ink can be supplied to the ink supply port 71 simply by discharging the ink from the ink discharge portion 81 without performing the ink sucking by the pump 303 described above.
After the ink has reached the ink supply port 71, as the ink sucking operation by the pump 303 and the ink discharge operation is continuously repeated, the negative pressure is generated inside of the liquid storage portion 80 according to the amount of ink discharged from the ink discharge portion 81. By the negative pressure, an ink meniscus formed at the ink supply port 71 is broken and the ink droplets drop into the ink buffer 90.
When the raised ink liquid surface 701 exceeds the height of the opening 91, the ink flows out of the ink buffer 90 via the opening 91 and is absorbed by the ink holding member 84. When the ink liquid surface 701 in the ink buffer 90 is raised, the same amount of ink as the raised volume of ink is supplied from the ink tank 15 to the ink buffer 90 via the ink supply path 14. By repeating this operation, the ink in the ink tank 15 is continuously supplied to the recording head 13 via the ink supply path 14.
The operation of ink supply from the ink buffer 90 to the ink holding member 84 is performed even during the recording operation of the recording apparatus 1. At this time, the ink supply port 71 is downward in the Z direction with respect to the ink liquid surface 701 (downward in the direction of the gravitational force with respect to the ink liquid surface 701).
An upstream side of the ink supply path 14 communicates with the atmosphere via the ink tank 15, and a downstream side of the ink supply path 14 is in contact with the atmosphere via the ink discharge portion 81. When the air in the recording head 13 expands due to a temperature rise or an atmospheric pressure drop, the pressure inside the recording head 13 increases. Since the discharge port of the ink discharge portion 81 is extremely small in diameter, withstanding pressure of the meniscus at the discharge port is very high. In a case where the pressure inside the recording head 13 becomes higher than the withstanding pressure of the meniscus at the discharge port of the ink discharge portion 81, the meniscus becomes broken. On the other hand, in a case where the pressure inside the recording head 13 is equal to or less than the withstanding pressure of the meniscus at the discharge port of the ink discharge portion 81, the ink liquid surface 701 in the ink buffer 90 is pressed downward by the air expanding in the recording head 13.
In the present exemplary embodiment, the opening 91 in the ink buffer 90 is formed at a position higher than the lower end of the ink supply port 71 in the Z direction. Thus, in a case where the air in the liquid storage portion 80 expands, the air does not enter the ink supply path 14 until the ink liquid surface 701 becomes under the lower end of the ink supply port 71. Therefore, the ink supply port 71 is desirably provided downward in the Z direction as much as possible with respect to the opening 91.
As illustrated in
Thus, when the recording apparatus 1 is re-installed in a posture for performing the recording operation as illustrated in
Providing an ink retaining unit 901 (liquid retaining unit) around the ink supply port 71 makes it possible to, even if the recording apparatus 1 is left upside down, retain the ink in the ink retaining unit 901. This more reliably prevents the entry of the air into the ink supply path 14 even in the case of expansion of the air in the recording head 13.
In the present modification, when the recording apparatus 1 is placed upside down, a liquid surface of the ink retained in the ink retaining unit 901 comes upward in the Z-axis direction with respect to the ink supply port 71.
A leading end of the ink retaining unit 901 is located upward in the Z direction (the direction of the gravitational force) with respect to the ink supply port 71, in a case where the recording apparatus 1 is placed upside down.
During the recording operation of the recording apparatus 1, the movement of the carriage 30 causes an X-direction inertial force to act on the ink in the ink buffer 90 to move the ink. For example, immediately before the reversal operation of the carriage 30 after the movement toward the maintenance unit 40, a −X inertial force acts on the ink in the ink buffer 90. Thus, the ink liquid surface 701 moves in such a manner to incline to the −X direction in the ink buffer 90. At this time, if the opening 91 is opened at a position displaced from the center to the −X direction, the ink moved in the ink buffer 90 may flow out of the opening 91 and be supplied to the ink holding member 84. In addition, the ink moved in the ink buffer 90 may become scattered via the opening 91 to various areas in the recording head 13 to make unstable the ink supply to the ink holding member 84.
Thus, the opening 91 in the ink buffer 90 is desirably opened to a direction crossing the X direction that is the scanning direction of the carriage 30. In the present exemplary embodiment, among side surfaces of the ink buffer 90, the opening 91 is desirably opened in a side surface along an XZ plane. Further, in the present exemplary embodiment, the opening 91 is desirably opened in the vicinity of the center in the X direction of the side surface along the XZ plane.
According to this configuration, it is possible to, even if the ink moves by the X-direction inertial force due to the movement of the carriage 30, reduce fluctuation in the ink supply resulting from fluctuation in the height of the ink liquid surface 701. This suppresses overflow of the ink from the ink buffer 90 due to scanning by the carriage 30, thereby allowing stable ink supply to the ink holding member 84.
A second exemplary embodiment will be described below. Description of components similar to those in the first exemplary embodiment described above will be omitted.
In the event of a temperature rise or an atmospheric pressure drop around a recording apparatus 1, the air in the recording head 13 expands according to the amount of change. Thus, as the proportion of an air layer in a liquid storage portion 80 is greater, the drop of a liquid surface of the ink in the ink buffer 90 is more affected by the expansion of the volume of an air layer portion. Thus, the proportion of the volume of the air layer in the recording head 13 is desirably small enough in comparison to the proportion of the volume of the ink holding member 84. Therefore, increasing the volume of the ink holding member 84 as in the present exemplary embodiment reduces the effect of the expansion of the volume of the air layer portion on the drop of an ink liquid surface 701 in the ink buffer 90.
In either the first exemplary embodiment or the second exemplary embodiment, the advantageous effects of the present disclosure can be obtained even if the ink holding member 84 is arranged upward in the Z-axis direction with respect to a top surface of the ink buffer 90.
The recording head 13 in the present disclosure can be a long line head in which discharge ports are arranged in an area corresponding to a width of a recording medium.
According to the present disclosure, it is possible to provide a recording apparatus that, even if the air in a recording head expands due to a temperature change or an atmospheric pressure change, suppresses the air from entering into a supply path.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of priority from Japanese Patent Application No. 2021-091749, filed May 31, 2021, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2021-091749 | May 2021 | JP | national |
Number | Name | Date | Kind |
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7445325 | Aikawa | Nov 2008 | B2 |
7686438 | Ogawa | Mar 2010 | B2 |
9139012 | Yamada | Sep 2015 | B2 |
Number | Date | Country |
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2017-081075 | May 2017 | JP |
Number | Date | Country | |
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20220379626 A1 | Dec 2022 | US |