JP2012030398A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus that prevents leakage of ink stored in a subink tank.SOLUTION: The inkjet recording apparatus includes: a subink tank 24 which is arranged at a position lower than a recording head 22, temporarily stores the ink stored in a main ink tank 23 and supplies the ink to the recording head 22, and has a subink tank upper hole 245; a first waste ink tank 26 having an atmosphere communication hole 264 for allowing the atmosphere to communicate with the inside of the first waste ink tank 26 and a waste ink tank upper hole 265, which is arranged at a position lower than the recording head 22 and stores the ink that overflows from the subink tank 24 upper hole 245 through the waste ink tank upper hole 265; and a communication path 121 for discharging the ink overflowing from the subink tank 24 to the first waste ink tank 26 through a position lower than the recording head 22 by allowing the inside of the subink tank 24 to communicate with the atmosphere via the first waste ink tank 26.

Description

  The present invention relates to an ink jet recording apparatus that performs recording on a recording medium such as paper by ejecting ink from an ink ejecting nozzle of a recording head.

  2. Description of the Related Art Conventionally, as an ink jet recording apparatus that performs recording on a recording medium such as paper, a recording head having a nozzle surface on which ink ejection nozzles are formed, a main ink tank that stores ink supplied to the recording head, and main ink There is known an ink jet recording apparatus that includes a sub ink tank that temporarily stores ink stored in a tank and supplies ink to a recording head.

In such an ink jet recording apparatus, an ink jet recording apparatus including a sub ink tank that is disposed at a position lower than the recording head and has a communication hole that communicates the atmosphere with the inside of the sub ink tank is known (for example, , See Patent Document 1).
In the ink jet recording apparatus described in Patent Document 1, the sub ink tank is disposed at a position lower than the recording head, so that the height of the liquid level of the ink stored in the sub ink tank and the nozzle surface of the recording head are high. By providing a difference in height (water head difference), ink leakage from the ink ejection nozzles of the recording head can be suppressed.

  In the technology that suppresses ink leakage from the ink ejection nozzles of the recording head using the water head difference, the sub ink tank is provided with a communication hole that communicates the inside and the atmosphere to increase the ink pressure difference due to gravity. Replace with the difference in height and set as the head difference. An ink jet recording apparatus that uses the water head difference can suppress ink leakage from the ink ejection nozzles of the recording head with a simple configuration.

Japanese Patent Laid-Open No. 2008-23806

  However, since the ink jet recording apparatus described in Patent Document 1 has a communication hole that communicates the atmosphere with the inside of the sub ink tank, when a large amount of ink is supplied from the main ink tank to the sub ink tank, Ink may leak into the ink jet recording apparatus through the communication hole. Therefore, there is a demand for an ink jet recording apparatus that can suppress leakage of ink stored in the sub ink tank while utilizing the water head difference technique.

  The present invention provides an ink jet recording apparatus that includes a sub ink tank that is disposed at a position lower than a recording head and communicates with the atmosphere, and that can suppress leakage of ink stored in the sub ink tank. With the goal.

  The present invention relates to a recording head having an ink ejection nozzle, a main ink tank that stores ink supplied to the recording head, and an ink that is disposed at a position lower than the recording head and is stored in the main ink tank. A sub ink tank having an upper hole on the upper side and a first waste ink tank disposed at a position lower than the recording head, And an air communication hole that communicates the atmosphere with the inside of the first waste ink tank, and a waste ink tank upper hole that is provided on the upper side, and overflows from the sub ink tank upper hole. A first waste ink tank for containing ink through the waste ink tank upper hole; and one end connected to the sub ink tank upper hole and the other end A communication path connected to the upper hole of the waste ink tank and communicating the interior of the sub ink tank and the atmosphere via the first waste ink tank, and the ink overflowing from the sub ink tank The present invention relates to an ink jet recording apparatus including a communication path that discharges to a first waste ink tank through a lower position.

  The sub ink tank is preferably disposed at a position higher than the first waste ink tank.

  In addition, one or a plurality of main ink tanks are provided, and the capacity of ink that can be stored in the first waste ink tank is equal to or greater than the total capacity of ink that can be stored in the one or more main ink tanks. Is preferred.

  Further, it is preferable to further include a second waste ink tank that stores the ink discharged from the ink ejection nozzle.

  A detection sensor for detecting the amount of ink stored in the first waste ink tank; and the ink stored in the first waste ink tank when the amount of ink detected by the detection sensor is equal to or greater than a predetermined threshold. It is preferable to further include a notification unit that notifies that the amount of ink is equal to or greater than a predetermined amount.

  According to the present invention, there is provided an ink jet recording apparatus that has a sub ink tank that is disposed at a position lower than a recording head and communicates with the atmosphere, and that can suppress leakage of ink stored in the sub ink tank. can do.

1 is a longitudinal sectional view schematically showing an outline of an inkjet recording apparatus 1 according to an embodiment of the present invention from the front side. FIG. 2 is a plan view showing the periphery of the recording unit 20 and the transport unit 30 in a state where a cap unit 50 is attached to each recording head 22 in the inkjet recording apparatus 1 of the present embodiment. FIG. 2 is a schematic configuration diagram schematically showing a configuration of an ink supply / drainage unit 100 in the inkjet recording apparatus 1 of the present embodiment. 5 is a flowchart for explaining the operation of the ink supply / drainage unit 100 immediately after the power is turned on in the inkjet recording apparatus 1 of the present embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The outline of the overall structure of the ink jet recording apparatus 1 of this embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a longitudinal sectional view schematically showing an outline of an ink jet recording apparatus 1 according to an embodiment of the present invention from the front side. FIG. 2 is a plan view showing the periphery of the recording unit 20 and the transport unit 30 in a state in which the cap unit 50 is mounted corresponding to each recording head 22 in the inkjet recording apparatus 1 of the present embodiment.

As shown in FIGS. 1 and 2, the inkjet recording apparatus 1 of the present embodiment includes a recording unit 20, a cleaning unit 25, a transport unit 30, an ink supply / drainage unit 100, and a transport unit in a main body 2. Lifting device 40 that lifts and lowers 30, cap unit 50, first horizontal movement mechanism (not shown) that horizontally moves cap unit 50, and second horizontal movement mechanism (not shown) that horizontally moves cleaning unit 25. With.
The ink jet recording apparatus 1 of the present embodiment further includes a paper feed cassette 3, a paper feed roller 4, a paper transport path 5, a registration roller pair 6, a drying device 7, a paper discharge roller pair 8, and paper discharge. A mouth 9 and a paper discharge tray 10 are provided.

  As shown in FIGS. 1 and 2, the transport unit 30 includes a drive roller 32, a driven roller 33, a transport belt 31 that is stretched over the drive roller 32 and the driven roller 33, and a tension that adjusts the tension of the transport belt 31. The roller 34 and an air suction unit (not shown) provided on the lower side of the conveying surface of the conveying belt 31 (on the side opposite to the recording unit 20). A number of through holes (not shown) for suction are provided on the upper surfaces of the transport belt 31 and the air suction unit, respectively.

When the driving roller 32 and the driven roller 33 rotate counterclockwise when viewed from the front, the transport surface 31A formed by the upper surface portion of the transport belt 31 is one of the paper transport directions P in the horizontal plane (XY plane). Horizontally to the other. That is, on the conveyance surface 31 </ b> A of the conveyance belt 31, the sheet conveyance direction P substantially coincides with the horizontal direction X. The air suction unit is disposed below the conveyance surface 31A of the conveyance belt 31 (on the side opposite to the recording unit 20), and applies a suction force that attracts the paper T as a recording medium to the conveyance surface 31A of the conveyance belt 31. .
As the conveyor belt 31, a belt in which both ends are overlapped and joined to form an endless shape, a seamless belt (seamless), or the like can be used.

  As shown in FIG. 2, at the time of predetermined recording, the paper T as a recording medium is introduced onto the transport surface 31 </ b> A of the transport belt 31 from one side in the paper transport direction P. A suction force acting on the transport belt 31 is generated on the transport surface 31A through the suction through-hole (not shown) with the operation of the air suction unit (not shown). The paper T introduced onto the transport surface 31A of the transport belt 31 is attracted to the transport surface 31A by the suction force and transported toward the other side in the paper transport direction P. Thus, an image or the like is recorded on the paper T by ejecting ink from the recording head 22 of the recording unit 20 to be described later toward the paper T being transported while being attracted to the transport surface 31A of the transport belt 31. (Printed).

  As shown in FIG. 1, the paper feed cassette 3 accommodates the paper T in a stacked state, and is disposed on the upstream side of the paper transport direction P of the transport unit 30 below the inside of the main body 2. The paper feed roller 4 is disposed above the paper feed cassette 3. The paper feed roller 4 feeds the paper T toward the upper right of the paper feed cassette 3 in FIG.

  The sheet conveyance path 5, the registration roller pair 6, the recording unit 20, and the conveyance unit 30 are arranged on the downstream side of the sheet feeding cassette 3 in the sheet conveyance direction P. The paper T sent out from the paper feed cassette 3 reaches the registration roller pair 6 through the paper transport path 5. The registration roller pair 6 corrects the oblique feeding of the paper T and feeds the paper T again. The leading edge of the paper T is detected by a paper leading edge detection sensor (not shown) provided in the paper conveyance path 5 between the recording unit 20 and the registration roller pair 6, and recording is performed based on the detected timing. The unit 20 performs an ink ejection operation as will be described later.

  As shown in FIG. 1, the drying device 7 is arranged on the downstream side in the paper transport direction P of the transport unit 30 above the inside of the main body 2. The drying device 7 dries the ink on the paper T after being recorded by the ink ejected by the recording unit 20.

  The paper discharge roller pair 8, the paper discharge port 9, and the paper discharge tray 10 are arranged in this order on the downstream side in the paper transport direction P of the drying device 7. The paper T, which has been dried by the drying device 7, is sent to the downstream side in the paper transport direction P by the paper discharge roller pair 8, and passes through the paper discharge port 9 to the paper discharge tray 10 provided outside the main body 2. Sent to the outside of the main body 2.

  As shown in FIGS. 1 and 2, the recording unit 20 includes recording heads 22 corresponding to four colors. The recording heads 22 corresponding to the four colors are a black recording head 22K, a cyan recording head 22C, a magenta recording head 22M, and a yellow recording head 22Y. These four color recording heads 22K, 22C, 22M, and 22Y extend long along the paper width direction Y orthogonal to the paper transport direction P (horizontal direction X). The recording heads 22 </ b> K, 22 </ b> C, 22 </ b> M, and 22 </ b> Y are arranged in order from the upstream side to the downstream side in the paper transport direction P along the paper transport direction P of the transport belt 31. In the present embodiment, one recording head is arranged for each color recording head in each of the four color recording heads 22K, 22C, 22M, and 22Y.

  The four color recording heads 22K, 22C, 22M, and 22Y have nozzle surfaces 221 (see FIG. 3) on which ink ejection nozzles are formed. The nozzle surface 221 is the lower surface of the four color recording heads 22K, 22C, 22M, and 22Y. The nozzle surface 221 in each of the recording heads 22K, 22C, 22M, and 22Y faces the conveyance surface 31A of the conveyance belt 31. The four-color recording heads 22K, 22C, 22M, and 22Y record an image on the paper T with the ink ejected from the ink ejection nozzles formed on the nozzle surface 221.

As shown in FIG. 1, the ink supply / drainage unit 100 includes four main ink tanks 23K, 23C, 23M, 23Y, four sub ink tanks 24K, 24C, 24M, 24Y, and one first waste ink tank. 26 as a main component.
The four main ink tanks 23K, 23C, 23M, and 23Y are disposed above the transport unit 30 corresponding to the four color recording heads 22K, 22C, 22M, and 22Y, respectively. The four main ink tanks 23K, 23C, 23M, and 23Y contain the inks that are supplied to the four color recording heads 22K, 22C, 22M, and 22Y. The ink of each color stored in the four main ink tanks 23K, 23C, 23M, and 23Y is supplied to four sub ink tanks 24K, 24C, 24M, and 24Y, which will be described later. The four main ink tanks 23K, 23C, 23M, and 23Y are arranged in order from the upstream side to the downstream side in the paper transport direction P along the paper transport direction P of the transport belt 31.

The four sub ink tanks 24K, 24C, 24M, and 24Y are disposed below the transport unit 30 corresponding to the four main ink tanks 23K, 23C, 23M, and 23Y, respectively. The four sub ink tanks 24K, 24C, 24M, and 24Y temporarily store the inks of the respective colors stored in the four main ink tanks 23K, 23C, 23M, and 23Y. The four sub ink tanks 24K, 24C, 24M, and 24Y are arranged in order from the upstream side to the downstream side in the paper transport direction P along the paper transport direction P of the transport belt 31.
The ink of each color stored in the four sub ink tanks 24K, 24C, 24M, 24Y is supplied from the four sub ink tanks 24K, 24C, 24M, 24Y to the recording heads 22K, 22C, 22M, 22Y of four colors. .

The first waste ink tank 26 is disposed below the four sub ink tanks 24K, 24C, 24M, and 24Y. The first waste ink tank 26 stores ink overflowing from the four sub ink tanks 24K, 24C, 24M, and 24Y.
Details of the ink supply / drainage unit 100 will be described later.

  In the following description, unless otherwise specified, the four color recording heads 22K, 22C, 22M, 22Y, the four main ink tanks 23K, 23C, 23M, 23Y, and the four sub ink tanks are used. For 24K, 24C, 24M, and 24Y, the identification symbols “K”, “C”, “M”, and “Y” are omitted, and “recording head 22”, “main ink tank 23”, and It is described as “Sub ink tank 24”.

  Each recording head 22 of the recording unit 20 is placed on the conveyance surface 31A of the conveyance belt 31 corresponding to image data information (for example, characters, figures, patterns) received from an external computer (not shown). Four colors of ink are ejected toward the paper T. As shown in FIG. 2, each recording head 22 is supported by a rectangular plate-shaped recording head support member 21, and is fixed to the main body 2 together with the recording head support member 21. Then, with the rotational movement of the transport belt 31, four color inks are sequentially ejected from each recording head 22 at a predetermined timing, so that the four color inks of black, cyan, magenta, and yellow are superimposed on the paper T. The color ink images are printed together.

  As an ink discharge method of the recording head 22, for example, a piezo method that pushes out ink using a piezo element (not shown), or bubbles are generated by a heating element (not shown), and ink is discharged by applying pressure. Various discharge methods such as a thermal ink jet method can be adopted.

  As shown in FIG. 1, the lifting device 40 that raises and lowers the transport unit 30 is disposed below the transport unit 30. The lifting device 40 moves the transport unit 30 up and down (moves) with respect to the recording head 22 in a direction Z (hereinafter also referred to as “vertical direction Z”) perpendicular to the horizontal plane (XY plane). By the movement of the transport unit 30 in the vertical direction Z by the lifting device 40, the transport surface 31 </ b> A of the transport belt 31 is configured to be relatively close to or away from the nozzle surface 221 (see FIG. 3) of the recording head 22. ing.

  As shown in FIG. 1, the lifting device 40 includes two eccentric cams 41 disposed on the upstream side and the downstream side in the paper transport direction P below the transport belt 31. A total of four eccentric cams 41 are provided, two on each of the front side and the back side of the transport unit 30. The eccentric circumferential surface of the eccentric cam 41 approaches the outer bottom surface of the transport unit 30 from below. As shown in FIG. 1, each eccentric cam 41 includes a shaft portion 42 extending in the paper width direction Y, and is constituted by a cam having a rotational axis that is unevenly distributed. The eccentric cam 41 is rotated around the shaft portion 42 via a motor (not shown). The eccentric cam 41 includes a plurality of bearings 43 at the peripheral edge thereof. A part of the peripheral surface of the bearing 43 protrudes outward from the peripheral surface of the eccentric cam 41.

  The bearing 43 is rotatable about an axis parallel to the rotation axis of the eccentric cam 41. The bearings 43 are sequentially arranged from the distal end side of the eccentric cam 41 toward the rotation axis side. In a normal printing state, as shown in FIG. 1, the bearing 43 farthest from the shaft portion 42 contacts the outer bottom surface of the transport unit 30 from below. Thereby, the transport unit 30 is moved up to the highest position.

From this state, the eccentric cam 41 on the upstream side in the paper transport direction P is rotated counterclockwise in front view, and the eccentric cam 41 on the downstream side in the paper transport direction P is rotated clockwise in front view. Accordingly, the plurality of bearings 43 sequentially contact the outer bottom surface of the transport unit 30 in order of the bearing 43 farthest from the shaft portion 42 to the bearing 43 closest to the shaft portion 42. Therefore, the transport unit 30 can be lowered.
The plurality of bearings 43 are arranged at intervals such that when the eccentric cam 41 rotates, the two bearings 43 adjacent in the peripheral direction simultaneously have a period of contact with the outer bottom surface of the transport unit 30.

  By rotating the eccentric cam 41 of the elevating device 40 and lowering the transport unit 30, the transport surface 31 </ b> A of the transport belt 31 in the transport unit 30 is separated downward with respect to the recording head 22.

  As shown in FIG. 1, the cap unit 50 is configured to be disposed below the recording unit 20 and above the conveyance unit 30 (between the recording unit 20 and the conveyance unit 30). As shown in FIG. 2, the cap unit 50 includes a plurality of cap cases 52 provided corresponding to the respective recording heads 22 and a cap base member 53 that fixes and supports the plurality of cap cases 52 in a predetermined positional relationship. .

  The cap unit 50 is configured to be movable up and down in conjunction with the lifting and lowering of the transport unit 30 by the lifting device 40 in a state where the cap unit 50 is disposed between the recording unit 20 and the transport unit 30. By rotating the eccentric cam 41 of the elevating device 40 and lowering the transport unit 30, the cap unit 50 is separated downward with respect to the recording head 22 in conjunction with the lowering of the transport surface 31 </ b> A of the transport belt 31. .

  As a result, the cap unit 50 is detached from the recording head 22. Then, in a state where the cap unit 50 is detached from the recording head 22, by ejecting ink from an ink ejecting nozzle (not shown) on the nozzle surface 221 of the recording head 22, the residual ink remaining in the ink ejecting nozzle is high. It is possible to execute a discharge recovery process for discharging ink having a viscosity to eliminate ink clogging, that is, purge.

  On the other hand, the conveyance unit 30 is returned to the normal recording position (printing position) by rotating the eccentric cam 41 of the elevating device 40 in the direction opposite to the above to raise the conveyance unit 30.

  Here, in a state where the cap unit 50 is disposed between the recording unit 20 and the transport unit 30, the cap unit 50 can be mounted on the nozzle surface 221 (see FIG. 3) of the recording head 22. Become. When the cap unit 50 is not disposed between the recording unit 20 and the transport unit 30 by a first horizontal movement mechanism (not shown) described later, the recording head 22 is placed on the transport surface 31A of the transport belt 31. Ink can be ejected toward the loaded paper T.

  The cap unit 50 is configured to be horizontally movable in the paper transport direction P (see FIG. 1) when the cap base member 53 is moved in the horizontal direction by a first horizontal movement mechanism (not shown).

  The position of the cap unit 50 is switched to an attaching / detaching position where the cap case 52 can be attached to and detached from each recording head 22 or a retreating position away from the attaching / detaching position in the horizontal direction by a moving operation by the first horizontal moving mechanism. During the recording operation in the recording unit 20, the cap unit 50 is disposed at the retracted position.

  The cleaning unit 25 is configured to be disposed below the cap unit 50 and above the transport unit 30 (between the cap unit 50 and the transport unit 30). Similar to the cap unit 50, the cleaning unit 25 is configured to be movable up and down in conjunction with the lifting and lowering of the transport unit 30 by the lifting device 40 in a state of being disposed between the cap unit 50 and the transport unit 30.

  The cleaning unit 25 is configured to be horizontally movable in the paper transport direction P (see FIG. 1) by a second horizontal movement mechanism (not shown). The cleaning unit 25 is a wipe position that is disposed below each recording head 22 and can clean each recording head 22 by a moving operation by the second horizontal movement mechanism, or a retreat position that is separated from the wipe position in the horizontal direction. Can be switched to. During a recording operation in the recording unit 20 or when the cap unit 50 is mounted on the nozzle surface 221 (see FIG. 3) of the recording head 22, the cleaning unit 25 is disposed at the retracted position.

  Hereinafter, with reference to FIG. 3, a configuration related to the ink supply / drainage unit 100, which is a characteristic part of the inkjet recording apparatus 1 of the present embodiment, will be described in detail. FIG. 3 is a schematic configuration diagram schematically illustrating the configuration of the ink supply / drainage unit 100 in the inkjet recording apparatus 1 of the present embodiment.

  As shown in FIG. 3, the ink supply / drainage unit 100 includes a recording head 22, a main ink tank 23, a sub ink tank 24, a first waste ink tank 26, a second waste ink tank 27, and a cap case. 52, the first ink supply path 122, the second ink supply path 123, the communication path 121, the ink discharge path 124, the first pump 105, the second pump 106, the on-off valve 109, and the first liquid. The surface detection sensor 107, the 2nd liquid level detection sensor 108 as a detection sensor, the valve opening / closing drive part 110, and the control part 150 are provided.

  As described above, the recording head 22 has the nozzle surface 221 on which ink ejection nozzles are formed. The recording head 22 records an image on the paper T with the ink ejected from the ink ejecting nozzles formed on the nozzle surface 221.

  The main ink tank 23 stores ink supplied to the recording head 22. The ink stored in the main ink tank 23 is supplied to a sub ink tank 24 (described later) via a first ink supply path 122 (described later).

  The sub ink tank 24 is disposed at a position lower than the main ink tank 23. The sub ink tank 24 is disposed at a position lower than the recording head 22. The sub ink tank 24 temporarily stores the ink stored in the main ink tank 23. The sub ink tank 24 supplies ink to the recording head 22. In other words, the ink stored in the sub ink tank 24 is supplied to the recording head 22 via the second ink supply path 123 (described later).

  The first ink supply path 122 connects the main ink tank 23 and the sub ink tank 24. The first ink supply path 122 is configured by a cylindrical tube extending in a substantially vertical direction. The first ink supply path 122 supplies the ink stored in the main ink tank 23 to the sub ink tank 24. The upstream end of the first ink supply path 122 is connected to the bottom of the main ink tank 23. The downstream end of the first ink supply path 122 is connected to the sub ink tank 24 and opens into the ink stored in the sub ink tank 24 while being separated from the bottom of the sub ink tank 24. ing.

  The on-off valve 109 is provided in the middle of the first ink supply path 122. The on-off valve 109 is configured to be able to open or close the first ink supply path 122.

When the on-off valve 109 is open, the ink stored in the main ink tank 23 can flow toward the sub ink tank 24 through the first ink supply path 122. Further, when the on-off valve 109 is in the closed state, the ink stored in the main ink tank 23 cannot flow toward the sub ink tank 24 through the first ink supply path 122.
As the on-off valve 109, for example, an electromagnetic on-off valve or an electric on-off valve is used. The on-off valve 109 is switched between an open state and a closed state by a valve opening / closing drive unit 110 described later.

  In the present embodiment, the sub ink tank 24 is disposed at a position lower than the main ink tank 23, and the first ink supply path 122 is disposed so as to extend in a substantially vertical direction. Therefore, the ink stored in the main ink tank 23 is supplied to the sub ink tank 24 through the first ink supply path 122 by gravity when the on-off valve 109 is open.

The sub ink tank 24 has a sub ink tank upper hole 245 on the upper side. One end of a communication path 121 (described later) is connected to the sub ink tank upper hole 245. The other end of the communication path 121 (described later) is connected to a first waste ink tank 26 (described later). Therefore, the inside of the sub ink tank 24 and the inside of the first waste ink tank 26 (described later) are communicated via the communication path 121 (described later).
Although details will be described later, the interior of the first waste ink tank 26 (described later) communicates with the atmosphere through an atmosphere communication hole 264 (described later). Therefore, the interior of the sub ink tank 24 is communicated with the atmosphere via a first waste ink tank 26 (described later).

  As described above, the sub ink tank 24 is disposed at a position lower than the recording head 22, and the inside thereof communicates with the atmosphere. In this way, a height difference (water head difference) H is provided between the liquid level of the ink stored in the sub ink tank 24 and the nozzle surface 221 of the recording head 22. Since the nozzle surface 221 of the recording head 22 is positioned higher than the liquid level of the ink stored in the sub ink tank 24, ink leakage from the ink ejection nozzles formed on the nozzle surface 221 of the recording head 22 Can be suppressed.

  The ink stored in the sub ink tank 24 overflows from the sub ink tank 24 via the sub ink tank upper hole 245 when the liquid level reaches the sub ink tank upper hole 245. The ink overflowing from the sub ink tank 24 is led out to the communication path 121 (described later) through the sub ink tank upper hole 245.

  The first waste ink tank 26 is disposed at a position lower than the sub ink tank 24. The first waste ink tank 26 is disposed at a position lower than the recording head 22.

The first waste ink tank 26 has an air communication hole 264 provided on the upper side, and a waste ink tank upper hole 265 provided on the upper side.
The air communication hole 264 opens outward in the upper part of the first waste ink tank 26. Thereby, the atmosphere communication hole 264 communicates the atmosphere with the inside of the first waste ink tank 26.

  The waste ink tank upper hole 265 opens at the upper part of the first waste ink tank 26. The other end of the communication path 121 (described later) is connected to the waste ink tank upper hole 265. The ink overflowing from the sub ink tank 24 passes through the communication path 121 and is stored in the first waste ink tank 26 via the waste ink tank upper hole 265.

  As described above, the first waste ink tank 26 stores the ink overflowing from the sub ink tank 24. The capacity of ink that can be stored in the first waste ink tank 26 is equal to or greater than the total capacity of ink that can be stored in the four main ink tanks 23K, 23C, 23M, and 23Y (see FIG. 1). That is, the first waste ink tank 26 is used when all of the ink stored in the four main ink tanks 23K, 23C, 23M, and 23Y is discharged through the four sub ink tanks 24K, 24C, 24M, and 24Y. All of the ink stored in the four main ink tanks 23K, 23C, 23M, and 23Y can be stored.

  The communication path 121 connects the sub ink tank 24 and the first waste ink tank 26. Specifically, one end on the upstream side of the communication path 121 is connected to the sub ink tank upper hole 245. The other end on the downstream side of the communication path 121 is connected to the waste ink tank upper hole 265.

  The communication path 121 is configured by a cylindrical tube that is curved in a substantially U-shape projecting upward. The top portion of the communication path 121 is located at a position lower than the recording head 22. The inner diameter of the tube constituting the communication path 121 is formed larger than the inner diameter of the tube constituting the first ink supply path 122.

  As described above, the inside of the first waste ink tank 26 is communicated with the atmosphere through the atmosphere communication hole 264. Therefore, the communication path 121 allows the inside of the sub ink tank 24 to communicate with the atmosphere via the first waste ink tank 26.

  Further, the communication path 121 discharges the ink overflowing from the sub ink tank 24 to the first waste ink tank 26 via a position lower than the recording head 22 (the top portion of the communication path 121).

  The second ink supply path 123 connects the sub ink tank 24 and the recording head 22. The second ink supply path 123 is configured by a cylindrical tube curved upward in a substantially U shape. The second ink supply path 123 supplies the ink stored in the sub ink tank 24 to the recording head 22. The upstream end portion of the second ink supply path 123 is connected to the side surface of the portion of the sub ink tank 24 where the ink is stored on the lower side. The downstream end of the second ink supply path 123 is connected to the upper part of the recording head 22.

  The first pump 105 is provided in the middle of the second ink supply path 123. The first pump 105 supplies the ink stored in the sub ink tank 24 toward the recording head 22 when performing the purge.

  The cap case 52 is provided corresponding to the recording head 22. The cap case 52 is disposed on the lower side of the corresponding recording head 22. The cap case 52 stores the ink ejected (discharged) from the ink ejection nozzles of the recording head 22 after the purge is executed.

  The second waste ink tank 27 is disposed at a position lower than the cap case 52. The second waste ink tank 27 stores ink discharged from the ink ejection nozzles of the recording head 22 stored in the cap case 52 via an ink discharge path 124 (described later).

  The ink discharge path 124 connects the cap case 52 and the second waste ink tank 27. The ink discharge path 124 is configured by a cylindrical tube. The ink discharge path 124 discharges the ink stored in the cap case 52 to the second waste ink tank 27. The upstream end of the ink discharge path 124 is connected to the bottom of the cap case 52. The downstream end of the ink discharge path 124 is connected to the upper part of the second waste ink tank 27 and opens to the inside of the second waste ink tank 27.

  The second pump 106 is provided in the middle of the ink discharge path 124. The second pump 106 sucks the ink stored in the cap case 52 and discharges the ink toward the second waste ink tank 27.

  The first liquid level detection sensor 107 is provided on the side surface of the sub ink tank 24. The first liquid level detection sensor 107 detects the amount of ink stored in the sub ink tank 24. The first liquid level detection sensor 107 detects that the level of the ink level stored in the sub ink tank 24 is less than a predetermined threshold value. Accordingly, the first liquid level detection sensor 107 detects that the amount of ink stored in the sub ink tank 24 is less than a predetermined amount.

As the predetermined threshold value, for example, the height of the ink level that can secure the amount of ink supplied to the recording head 22 for purging during the purge operation, the amount of ink supplied to the recording head 22 during printing, and the like. The height of the ink surface that can secure the amount, and the difference in height (water head difference) H between the ink surface for supplying ink to the recording head 22 and the nozzle surface 221 of the recording head 22 are secured. The height of the ink level that can be set is set.
When the first liquid level detection sensor 107 detects that the height of the ink liquid level is less than a predetermined threshold, the first liquid level detection sensor 107 outputs a detection signal to a valve opening / closing control unit 152 described later.

  The second liquid level detection sensor 108 is provided on the side surface of the first waste ink tank 26. The second liquid level detection sensor 108 detects the amount of ink stored in the first waste ink tank 26. The second liquid level detection sensor 108 detects that the height of the liquid level of the ink stored in the first waste ink tank 26 is equal to or greater than a predetermined threshold value. As the predetermined threshold, for example, in order to detect that the ink overflows from the sub ink tank 24 to the first waste ink tank 26, the lowest liquid level of the ink that can be detected by the second liquid level detection sensor 108 is used. The height can be set. When the second liquid level detection sensor 108 detects that the height of the ink liquid level is equal to or greater than a predetermined threshold value, the second liquid level detection sensor 108 outputs a detection signal to a notification unit 151 described later.

  The valve opening / closing drive unit 110 switches the opening / closing valve 109 to an open state or a closed state. The valve opening / closing drive unit 110 is controlled by a valve opening / closing control unit 152 described later.

The control unit 150 includes a notification unit 151, a valve opening / closing control unit 152, a first pump control unit 153, and a second pump control unit 154.
A warning display unit 155 is connected to the notification unit 151. The notification unit 151 monitors the detection signal output from the second liquid level detection sensor 108 and determines whether or not the liquid level of the ink stored in the first waste ink tank 26 is equal to or greater than a predetermined threshold value. Determine.

  The notification unit 151 indicates that the amount of ink stored in the first waste ink tank 26 is equal to or greater than a predetermined amount when the amount of ink detected by the second liquid level detection sensor 108 is equal to or greater than a predetermined threshold. Is notified. Specifically, for example, the notification unit 151 monitors the detection signal output from the second liquid level detection sensor 108 immediately after the power supply of the inkjet recording apparatus 1 is turned on, and sends it to the first waste ink tank 26. When it is determined that the liquid level of the ink stored is greater than or equal to a predetermined threshold, control is performed so that a message is displayed on the warning display unit 155.

  The valve opening / closing control unit 152 monitors the detection signal output from the first liquid level detection sensor 107 and determines whether or not the liquid level of the ink stored in the sub ink tank 24 is less than a predetermined threshold value. Determine. When it is determined that the level of the ink level stored in the sub ink tank 24 is less than a predetermined threshold, the valve opening / closing control unit 152 opens the valve opening / closing drive unit 110 so as to open the opening / closing valve 109. To control.

The first pump control unit 153 controls the first pump 105 so as to supply an amount of ink necessary for executing the purge from the sub ink tank 24 to the recording head 22 at the time of purging.
The second pump control unit 154 controls the second pump 106 so that the ink stored in the cap case 52 is sucked and discharged to the second waste ink tank 27.

Next, with reference to FIGS. 1 and 3, the operation of the ink supply / drainage unit 100 of the ink jet recording apparatus 1 of the present embodiment will be briefly described.
The user instructs a predetermined printing command to the ink jet recording apparatus 1. Thereby, the inkjet recording apparatus 1 receives a printing command. The ink jet recording apparatus 1 starts printing on the paper T.

  During printing, ink is supplied from the sub ink tank 24 to the recording head 22. Here, the ink supplied from the main ink tank 23 is stored in the sub ink tank 24.

  The ink supplied to the recording head 22 is ejected from the ink ejection nozzles on the nozzle surface 221 of the recording head 22 toward the paper T. Thus, predetermined printing is performed on the paper T.

  The amount of ink stored in the sub ink tank 24 is ensured not to be less than a predetermined amount. Specifically, the valve opening / closing control unit 152 monitors the detection signal from the first liquid level detection sensor 107, and the height of the liquid level of the ink stored in the sub ink tank 24 is less than a predetermined threshold value. It is determined whether or not. The valve opening / closing control unit 152 drives the valve opening / closing so that the opening / closing valve 109 is opened when it is determined that the level of the ink level stored in the sub ink tank 24 is less than a predetermined threshold. The unit 110 is controlled.

  Thus, when the amount of ink stored in the sub ink tank 24 is less than the predetermined amount, the ink stored in the main ink tank 23 opens the on-off valve 109 so that the first ink is generated by gravity. The sub ink tank 24 is replenished via the supply path 122. Accordingly, the amount of ink stored in the sub ink tank 24 is ensured to be equal to or greater than a predetermined amount.

Here, factors that cause the amount of ink stored in the sub ink tank 24 to be less than a predetermined amount include consumption of ink by printing, consumption of ink by purging, and the like.
The purge is performed at a predetermined timing in order to discharge ink with high viscosity remaining in the ink ejecting nozzles and eliminate ink clogging. At the time of purging, the first pump control unit 153 controls the first pump 105 so as to supply an amount of ink required for performing the purging from the sub ink tank 24 to the recording head 22. As a result, high viscosity ink remaining in the ink ejection nozzles is ejected, and ink clogging of the ink ejection nozzles is eliminated. After the purge is performed, the ink ejected from the ink ejection nozzles of the recording head 22 is stored in the cap case 52.

  Further, it is preferable that ink does not leak from the ejection nozzles of the recording head 22. Therefore, in the ink jet recording apparatus 1 according to the present embodiment, a water head difference H is provided between the liquid level of the ink stored in the sub ink tank 24 and the nozzle surface 221 of the recording head 22. Specifically, the sub ink tank 24 is disposed at a position lower than the recording head 22, and the inside of the sub ink tank 24 is in communication with the atmosphere. As a result, ink leakage from the ink ejection nozzles of the recording head 22 is suppressed.

  Further, as described above, after the purge is performed, the cap case 52 stores ink ejected from the ejection nozzles of the recording head 22. Therefore, the second pump control unit 154 controls the second pump 106 so that the ink stored in the cap case 52 is sucked and discharged to the second waste ink tank 27 at a predetermined timing. The ink stored in the cap case 52 is discharged and stored in the second waste ink tank 27. Thereby, the overflow of ink from the cap case 52 is suppressed.

  Incidentally, there is a case where a large amount of ink stored in the main ink tank 23 is supplied to the sub ink tank 24 due to breakage of the on-off valve 109 provided in the middle of the first ink supply path 122. When a large amount of ink is supplied to the sub ink tank 24, the ink level rises. When an amount of ink that cannot be stored in the sub ink tank 24 is supplied to the sub ink tank 24, the ink stored in the sub ink tank 24 overflows from the sub ink tank upper hole 245. .

  In the present embodiment, one end of the communication path 121 is connected to the sub ink tank upper hole 245. The other end of the communication path 121 is connected to the first waste ink tank 26. The communication path 121 is connected to the first waste ink tank 26 via a position lower than the recording head 22. The first waste ink tank 26 is disposed at a position lower than the recording head 22 and the sub ink tank 24.

  Therefore, the ink that cannot be stored in the sub ink tank 24 and overflows from the sub ink tank 24 is discharged to the first waste ink tank 26 through the communication path 121. As a result, the ink overflowing from the sub ink tank 24 is stored in the first waste ink tank 26, and is thus prevented from leaking into the ink jet recording apparatus 1.

  In addition, the cylindrical tube constituting the communication path 121 has a larger diameter than the tube constituting the first ink supply path 122. Therefore, the ink overflowing from the sub ink tank 24 smoothly passes through the communication path 121 and is discharged to the first waste ink tank 26.

  When a large amount of ink is stored in the sub ink tank 24, the ink also moves to the second ink supply path 123 side. Here, the first waste ink tank 26 is disposed at a position lower than the recording head 22. The communication path 121 is located at a position lower than the recording head 22 (the top portion of the communication path 121) for the ink overflowing from the sub ink tank 24 between the sub ink tank 24 and the first waste ink tank 26. It is arranged to go through.

  Therefore, the ink that has moved from the sub ink tank 24 to the second ink supply path 123 does not reach the recording head 22. Accordingly, it is possible to suppress ink leakage from the ink ejection nozzles of the recording head 22.

  The ink capacity that can be stored in the first waste ink tank 26 is equal to or greater than the total capacity of ink that can be stored in the four main ink tanks 23K, 23C, 23M, and 23Y (see FIG. 1). Therefore, all of the ink stored in the four main ink tanks 23K, 23C, 23M, and 23Y is stored in the first waste ink tank 26 via the four sub ink tanks 24K, 24C, 24M, and 24Y (see FIG. 1). Is possible.

  Accordingly, the first waste ink tank 26 can store all of the ink that may overflow from the four sub ink tanks 24K, 24C, 24M, and 24Y. As a result, all of the ink overflowing from the sub ink tank 24 is stored in the first waste ink tank 26, so that leakage into the ink jet recording apparatus 1 is further suppressed.

  Here, when the ink stored in the main ink tank 23 decreases, there are cases where new ink is replenished to the main ink tank 23 or replaced with the main ink tank 23 storing new ink. When the main ink tank 23 is replenished with ink or replaced with a new main ink tank 23, the ink discharged to the first waste ink tank 26 is the volume of ink that can be stored in the first waste ink tank 26. May be exceeded.

Therefore, it may be desired to detect that a predetermined amount or more of ink has been stored in the first waste ink tank 26 before the ink overflows from the first waste ink tank 26.
Further, by detecting the amount of ink stored in the first waste ink tank 26, it may be desired to detect an abnormality that a predetermined amount or more of the ink overflows from the sub ink tank 24.
Therefore, in this embodiment, the ink jet recording apparatus 1 detects the height of the liquid level of the ink stored in the first waste ink tank 26 immediately after the power is turned on.

  The operation of the ink supply / drainage unit 100 immediately after the power is turned on in the inkjet recording apparatus 1 of the present embodiment will be described below with reference to FIG. FIG. 4 is a flowchart for explaining the operation of the ink supply / drainage unit 100 immediately after the power is turned on in the inkjet recording apparatus 1 of the present embodiment.

  As shown in FIG. 4, in step ST1, the inkjet recording apparatus 1 is turned on by the user.

  In step ST <b> 2, the notification unit 151 monitors the detection signal from the second liquid level detection sensor 108 and determines whether the liquid level of the ink stored in the first waste ink tank 26 is equal to or greater than a predetermined threshold value. Determine whether or not. If it is determined that the liquid level of the ink stored in the first waste ink tank 26 is greater than or equal to a predetermined threshold (YES), the process proceeds to step ST3. If it is determined that the liquid level of the ink stored in the first waste ink tank 26 is less than the predetermined threshold (NO), the process proceeds to step ST4.

In step ST3, the notification unit 151 causes the warning display unit 155 to display a message. Thereby, the user can grasp that the height of the liquid level of the ink stored in the first waste ink tank 26 is not less than a predetermined level. Then, it is detected that the ink stored in the first waste ink tank 26 needs to be collected, or an abnormality that a predetermined amount of ink overflows from the sub ink tank 24 is detected. Can do.
In this case, for example, the inkjet recording apparatus 1 is shifted to a state where it does not accept a print command. And control is complete | finished in the state which displayed the message on the warning display part 155. FIG.

  In step ST4 when it is determined that the liquid level of the ink stored in the first waste ink tank 26 in step ST2 is less than the predetermined threshold (NO), the inkjet recording apparatus 1 receives the print command. It becomes possible. When the print command is instructed, the inkjet recording apparatus 1 accepts the print command.

  In step ST <b> 5, when the inkjet recording apparatus 1 receives a printing command, the ink stored in the sub ink tank 24 is supplied from the sub ink tank 24 to the recording head 22 via the second ink supply path 123. Thereby, predetermined printing is started. Then, the control ends.

According to the ink jet recording apparatus 1 of the present embodiment, for example, the following effects are exhibited.
In the inkjet recording apparatus 1 of the present embodiment, the recording head 22 having ink ejection nozzles, the main ink tank 23 that stores the ink supplied to the recording head 22, and the lower position than the recording head 22, The ink stored in the main ink tank 23 is temporarily stored and the ink is supplied to the recording head 22, and the sub ink tank 24 having the sub ink tank upper hole 245 on the upper side is disposed at a position lower than the recording head 22. An air communication hole 264 provided on the upper side and communicating the atmosphere and the inside of the first waste ink tank 26; a waste ink tank upper hole 265 provided on the upper side; And the ink overflowing from the sub ink tank upper hole 245 is accommodated through the waste ink tank upper hole 265. The first waste ink tank 26 has one end connected to the sub ink tank upper hole 245 and the other end connected to the waste ink tank upper hole 265, and the inside of the sub ink tank 24 through the first waste ink tank 26. And a communication path 121 that allows the ink overflowing from the sub ink tank 24 to be discharged to the first waste ink tank 26 via a position lower than the recording head 22. .

  Therefore, the sub ink tank 24 is arranged at a position lower than the recording head 22. Further, the interior of the sub ink tank 24 communicates with the atmosphere. Thus, a water head difference H is provided between the nozzle surface 221 of the recording head 22 and the liquid surface of the ink stored in the sub ink tank 24. Further, the ink overflowing from the sub ink tank 24 without being stored in the sub ink tank 24 is discharged to the first waste ink tank 26 via the communication path 121. Accordingly, it is possible to suppress the leakage of ink stored in the sub ink tank 24 while suppressing the leakage of ink from the ink ejection nozzles of the recording head 22.

  In the inkjet recording apparatus 1 of the present embodiment, the sub ink tank 24 is disposed at a position higher than the first waste ink tank 26. Therefore, the ink overflowing from the sub ink tank 24 is easily discharged to the first waste ink tank 26. Thereby, the leakage of the ink accommodated in the sub ink tank 24 can be further suppressed.

  In the inkjet recording apparatus 1 of the present embodiment, one or a plurality of main ink tanks 23 are provided, and the capacity of ink that can be stored in the first waste ink tank 26 is stored in one or more main ink tanks 23. It is more than the total possible ink capacity.

  Therefore, all of the ink stored in the four main ink tanks 23K, 23C, 23M, and 23Y can be stored in the first waste ink tank 26 via the four sub ink tanks 24K, 24C, 24M, and 24Y. As a result, the first waste ink tank 26 is used when all of the ink stored in the four main ink tanks 23K, 23C, 23M, and 23Y is discharged through the four sub ink tanks 24K, 24C, 24M, and 24Y. In addition, all of the ink stored in the four main ink tanks 23K, 23C, 23M, and 23Y can be stored. Therefore, it is possible to suppress the ink stored in the first waste ink tank 26 from leaking into the ink jet recording apparatus 1.

  Further, the inkjet recording apparatus 1 of the present embodiment further includes a second waste ink tank 27 that stores ink discharged from the ink ejection nozzles of the recording head 22. Therefore, the first waste ink tank 26 that stores the ink overflowing from the sub ink tank 24 is configured as an ink tank separate from the second waste ink tank 27.

Thereby, the ink overflowing from the sub ink tank 24 is stored only in the first waste ink tank 26. Accordingly, the amount of ink overflowing from the sub ink tank 24 can be easily grasped.
The first waste ink tank 26 stores only the ink overflowing from the sub ink tank 24. Accordingly, since the capacity of the ink that can be stored in the first waste ink tank 26 can be easily grasped, the capacity of the first waste ink tank 26 can be easily set.
Further, it is possible to detect that the ink overflows from the sub ink tank 24 only by monitoring the amount of ink stored in the first waste ink tank 26.

  In the inkjet recording apparatus 1 of the present embodiment, the second liquid level detection sensor 108 that detects the amount of ink stored in the first waste ink tank 26 and the ink detected by the second liquid level detection sensor 108. And a notification unit 151 for notifying that the amount of ink stored in the first waste ink tank 26 is equal to or greater than a predetermined amount when the amount is equal to or greater than a predetermined threshold.

  Therefore, it can be easily grasped that the amount of ink stored in the first waste ink tank 26 is equal to or greater than a predetermined amount. Thereby, before the ink overflows from the first waste ink tank 26, the ink can be collected from the first waste ink tank 26, and leakage of the ink stored in the first waste ink tank 26 can be suppressed. Further, it is possible to detect that a predetermined amount or more of ink has overflowed from the sub ink tank 24.

As mentioned above, although preferred embodiment of this invention was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above.
For example, in the above-described embodiment, the first waste ink tank 26 is arranged at a position lower than the sub ink tank 24. However, the present invention is not limited to this. The first waste ink tank 26 may be arranged at a position higher than the sub ink tank 24.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording device, 22 ... Recording head, 23 ... Main ink tank, 24 ... Sub ink tank, 26 ... First waste ink tank, 27 ... Second waste ink tank, 108 ... Second Liquid level detection sensor (detection sensor), 151 ... notification unit, 121 ... communication path, 245 ... sub-ink tank upper hole, 264 ... atmospheric communication hole, 265 ... waste ink tank upper hole

Claims (5)

A recording head having ink ejection nozzles;
A main ink tank for storing ink supplied to the recording head;
A sub ink tank which is disposed at a position lower than the recording head, temporarily stores the ink stored in the main ink tank and supplies the ink to the recording head, and has a sub ink tank upper hole on the upper side;
A first waste ink tank disposed at a position lower than the recording head, provided on the upper side, and provided on the upper side with an air communication hole that communicates the atmosphere with the inside of the first waste ink tank. A first waste ink tank having a waste ink tank upper hole, and accommodating ink overflowing from the sub ink tank upper hole through the waste ink tank upper hole;
One end is connected to the sub ink tank upper hole, and the other end is connected to the waste ink tank upper hole, and the communication path connects the inside of the sub ink tank and the atmosphere via the first waste ink tank. A communication path for discharging the ink overflowing from the sub ink tank to the first waste ink tank via a position lower than the recording head;
An inkjet recording apparatus comprising: The inkjet recording apparatus according to claim 1, wherein the sub ink tank is disposed at a position higher than the first waste ink tank. One or a plurality of the main ink tanks are provided,
3. The ink jet recording apparatus according to claim 1, wherein a volume of ink that can be stored in the first waste ink tank is equal to or greater than a total amount of ink that can be stored in the one or more main ink tanks. 4. The inkjet recording apparatus according to claim 1, further comprising a second waste ink tank that stores ink discharged from the ink ejection nozzle. 5. A detection sensor for detecting the amount of ink stored in the first waste ink tank;
And a notification unit for notifying that the amount of ink stored in the first waste ink tank is equal to or greater than a predetermined amount when the amount of ink detected by the detection sensor is equal to or greater than a predetermined threshold. Item 5. The ink jet recording apparatus according to any one of Items 1 to 4.

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