EP4721982A1

EP4721982A1 - Liquid supply unit, recording device provided with same, and method for attaching liquid supply unit

Info

Publication number: EP4721982A1
Application number: EP24819091.0A
Authority: EP
Inventors: Daisuke Eto
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2023-06-05
Filing date: 2024-05-13
Publication date: 2026-04-08
Also published as: CN121285472A; JPWO2024252854A1; WO2024252854A1

Abstract

A liquid supply unit includes a supply tank that stores a liquid to be supplied to a supply destination, a collection tank that stores the liquid collected from the supply destination, and a support that supports the supply tank and the collection tank. The support is detachably attachable to an apparatus body including the supply destination.

Description

TECHNICAL FIELD

The present disclosure relates to a liquid supply unit, a recording apparatus including the liquid supply unit, and a method for mounting the liquid supply unit.

BACKGROUND OF INVENTION

Patent Literature 1 describes an inkjet recording apparatus that prints on a medium with ink. With this technique, the inkjet recording apparatus includes a supply tank that stores ink, a recording head that ejects ink supplied from the supply tank, and a collection tank that stores ink collected from the recording head. The supply tank and the collection tank are independent of a box-like ink tank guide and are attachable to and detachable from the ink tank guide.

CITATION LIST

PATENT LITERATURE

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 07-060991

SUMMARY

In one aspect of the present disclosure, a liquid supply unit includes a supply tank, a collection tank, and a support. The supply tank stores a liquid to be supplied to a supply destination. The collection tank stores the liquid collected from the supply destination. The support supports the supply tank and the collection tank. The support is detachably attachable to an apparatus body including the supply destination.
In another aspect of the present disclosure, a recording apparatus includes the above liquid supply unit and an ejection head. The ejection head is the supply destination that receives the liquid and ejects the liquid onto a recording medium.
In still another aspect of the present disclosure, a method for mounting a liquid supply unit is a method for mounting a liquid supply unit on an apparatus body including a supply destination. The liquid supply unit includes a supply tank and a collection tank that each store a liquid. The method includes attaching the supply tank and the collection tank to a support and attaching the support to the apparatus body. The attaching the support to the apparatus body is performed with the supply tank and the collection tank attached to the support to allow the liquid to be supplied from the supply tank to the supply destination and to be collected from the supply destination to the collection tank.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a recording apparatus according to one embodiment of the present disclosure, illustrating its overall structure.
FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1.
FIG. 3 is an enlarged perspective view of a carriage illustrated in FIG. 1.
FIG. 4 is a schematic diagram illustrating a flow of ink near ink heads in one embodiment of the present disclosure.
FIG. 5 is a schematic diagram of a supply subtank and a collection subtank according to one embodiment of the present disclosure.
FIG. 6 is a perspective view of a tank unit according to one embodiment of the present disclosure.
FIG. 7 is a perspective view of a tank unit according to one embodiment of the present disclosure as viewed in a direction opposite to the direction in FIG. 6.
FIG. 8 is a perspective view of multiple tank units attached to a carriage in one embodiment of the present disclosure.
FIG. 9 is a perspective view of a heater in a tank unit according to an embodiment.
FIG. 10 is an exploded perspective view of the heater in the tank unit according to the embodiment.

DESCRIPTION OF EMBODIMENTS

A recording apparatus according to one embodiment of the present disclosure will now be described below with reference to the drawings. In one or more embodiments below, an inkjet printer including an ink head that ejects ink for image formation onto a wide and long recording medium will be described as a specific example of the recording apparatus. The inkjet printer may be used for digital textile printing to print images such as letters or patterns by inkjet printing on a recording medium including a textile such as woven fabric or knitted fabric. In one or more embodiments of the present disclosure, the recording apparatus is also used for printing various images on a recording medium such as a paper sheet or a resin sheet.

Overall Structure of Inkjet Printer

FIG. 1 is a perspective view of an inkjet printer 1 according to one embodiment of the present disclosure, illustrating its overall structure. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. The inkjet printer 1 is a printer that prints an image on a wide and long workpiece W (a recording medium or an object) by inkjet printing. An example workpiece W is several meters wide. The printer 1 includes an apparatus frame 10, and a workpiece feeder 20 and a carriage 3 (apparatus body) incorporated in the apparatus frame 10. Note that, in the present embodiment, a lateral direction is a main scanning direction S (FIG. 3) in printing on the workpiece W, and a direction from rear to front is a subscanning direction (a feed direction F of the workpiece W intersecting with the main scanning direction S).
The apparatus frame 10 is a frame on which various components of the inkjet printer 1 are mounted. The workpiece feeder 20 is an assembly that intermittently feeds (transports) the workpiece W to allow the workpiece W to move in the feed direction F from rear to front in a printing area in which an inkjet printing process is performed. The carriage 3 carries an ink head 4, a pretreatment liquid head 5, a post-treatment liquid head 6, and a subtank 7, and reciprocates in the main scanning direction S (lateral direction) intersecting with the feed direction F of the workpiece W during the inkjet printing process.
The apparatus frame 10 includes a center frame 111, a right frame 112, and a left frame 113. The center frame 111 is a frame on which various components of the inkjet printer 1 are mounted and has a lateral width corresponding to the workpiece feeder 20. The right frame 112 stands on the right of the center frame 111, and the left frame 113 stands on the left of the center frame 111. A printing area 12 in which a printing process is performed on the workpiece W is defined between the right frame 112 and the left frame 113.
The right frame 112 defines a maintenance area 13. The maintenance area 13 is an area into which the carriage 3 is retracted when the printing process is not performed. In the maintenance area 13, nozzles (ejection orifices) of the ink head 4, the pretreatment liquid head 5, and the post-treatment liquid head 6 are, for example, cleaned or purged, or each of the nozzles is capped. The left frame 113 defines a turn-back area 14 for the carriage 3. The turn-back area 14 is an area for the carriage 3 that has performed main scanning on the printing area 12 from right to left in the printing process to enter temporarily before performing main scanning in the reverse direction.
The apparatus frame 10 receives, on its upper portion, a carriage guide 15 for guiding the carriage 3 to reciprocate in the lateral direction. The carriage guide 15 is a flat plate elongated in the lateral direction and is located above the workpiece feeder 20. The carriage guide 15 receives a timing belt 16 rotatable in the lateral direction (main scanning direction). The timing belt 16 is an endless belt that is driven to rotate in the left direction or the right direction.
The carriage guide 15 includes a pair of upper and lower guide rails 17 holding the carriage 3 in a manner reciprocable in the main scanning direction S. The pair of guide rails 17 extend parallel to each other in the lateral direction. The carriage 3 is engaged with the guide rails 17. The carriage 3 is fixed to the timing belt 16. The carriage 3, while being guided by the guide rails 17, moves in the left direction or the right direction along the carriage guide 15 as the timing belt 16 rotates in the left direction or the right direction.
Referring mainly to FIG. 2, the workpiece feeder 20 includes a feed roller 21 that unwinds the workpiece W before printing, and a take-up roller 22 that winds the workpiece W after printing. The feed roller 21 is located in a lower rear portion of the apparatus frame 10. The feed roller 21 is a winding shaft of a feed roll WA as a wound roll of the workpiece W before printing. The take-up roller 22 is located in a lower front portion of the apparatus frame 10. The take-up roll is a winding shaft of a take-up roll WB as a wound roll of the workpiece W after the printing process. The take-up roller 22 includes a first motor M1 that rotates the take-up roller 22 about its axis to wind the workpiece W.
A path extending through the printing area 12 between the feed roller 21 and the take-up roller 22 is a feed path of the workpiece W. This feed path includes, in the order from upstream, a first tension roller 23, a workpiece guide 24, a transport roller 25 and a pinch roller 26, a turn roller 27, and a second tension roller 28. The first tension roller 23 applies a predetermined tension to the workpiece W upstream from the transport roller 25. The workpiece guide 24 redirects the workpiece W from upward to frontward and feeds the workpiece W into the printing area 12.
The transport roller 25 generates a feed force for feeding the workpiece W intermittently in the printing area 12. The transport roller 25, which is driven by a second motor M2, rotates about its axis and intermittently feeds the workpiece W frontward (in the predetermined feed direction F) to allow the workpiece W to pass through the printing area 12 (image formation position) facing the carriage 3. The pinch roller 26 faces the transport roller 25 from above and forms a feed nip with the transport roller 25.
The turn roller 27 redirects the workpiece W that has passed through the printing area 12 from frontward to downward, and guides the workpiece W after the printing process to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W downstream from the transport roller 25. A platen 29 is located below the feed path of the workpiece W in the printing area 12.
The carriage 3 reciprocates, while being held by the guide rails 17 in a cantilevered manner, in the main scanning direction S (the lateral direction in the present embodiment) intersecting with (perpendicular to in the present embodiment) the feed direction F. The carriage 3 includes a carriage frame 30 as well as the ink head 4, the pretreatment liquid head 5, the post-treatment liquid head 6, and the subtank 7 mounted on the carriage frame 30 (FIG. 3). The carriage frame 30 includes a head support frame 31 and a back frame 32.
The head support frame 31 is a horizontal plate holding the heads 4 to 6 described above. The back frame 32 is a vertical plate extending upward from a rear edge of the head support frame 31. As described above, the timing belt 16 is fixed to the back frame 32. The guide rails 17 are engaged with the back frame 32. In other words, the back frame 32 is an engaging portion held by the guide rails 17 in a cantilevered manner in the present embodiment. The head support frame 31 is a horizontal plate including a rear end portion held by the guide rails 17 in a cantilevered manner with the engaging portion.
Note that being held in a cantilevered manner refers to a state in which the engaging portion (back frame 32) in the carriage 3 held by the guide rails 17 as holding members is located upstream or downstream alone from the middle of the carriage 3 in the feed direction F, with no other engaging portion in an area opposite to the area including the engaging portion. The engaging portion may also be located outside an area including the ink head 4 and the treatment heads in the feed direction F. In other words, the engaging portion may be located upstream or downstream alone from the area including the ink head 4 and the treatment heads in the feed direction F.

Details of Carriage

The carriage 3 will be described further. FIG. 3 is an enlarged perspective view of the carriage 3 illustrated in FIG. 1. In FIG. 3, the feed direction F (subscanning direction) of the workpiece W and the main scanning direction S in which the carriage 3 moves are illustrated. In the example illustrated in FIG. 3, the carriage 3 carries multiple ink heads 4 that eject ink for image formation onto the workpiece W, the pretreatment liquid head 5 and the post-treatment liquid head 6 that eject noncolor-developing treatment liquids, and multiple subtanks 7 that supply the ink and the treatment liquids to the heads 4 to 6.
Each of the ink heads 4 includes many nozzles (ink ejection orifices) and an ink channel that guides ink to the nozzles. The nozzles eject ink droplets by, for example, piezoelectric ejection using piezoelectric elements or thermal ejection using heating elements. Examples of the ink include water-based pigment ink containing a water-based solvent, a pigment, and a bonding resin (binder). In the present embodiment, the multiple ink heads 4 can eject eight colors of ink. The ink heads 4 are mounted on the head support frame 31 in the carriage 3 (FIG. 2) in two arrays in the main scanning direction S. Two ink heads 4 are used for each of the colors.
More specifically, the ink heads 4 include a first upstream ink head 41A and a first downstream ink head 41B. These ink heads 4 eject yellow ink. The ink heads 4 also include a second upstream ink head 42A and a second downstream ink head 42B. These ink heads 4 eject magenta ink. In the same or a similar manner, two ink heads 4 that eject the same color of ink are arranged in a manner displaced from each other in the feed direction F and the main scanning direction S as illustrated in FIG. 3. With these two ink heads 4 being paired, a total of eight pairs of ink heads 4 (41A to 48A and 41B to 48B) eject different colors of ink (different liquids). Note that, in one or more embodiments of the present disclosure, different liquids refer to different types of liquids and also refer to liquids of the same type that flow through channels independent of each other.
The pretreatment liquid head 5 and the post-treatment liquid head 6 are at different positions from the ink heads 4 in the feed direction F. The pretreatment liquid head 5 is located upstream from the ink heads 4 in the feed direction F. In the example illustrated in FIG. 3, a single pretreatment liquid head 5 is located adjacent to the left end of an array of ink heads 4. In the same or a similar manner, the post-treatment liquid head 6 is located downstream from the ink heads 4 in the feed direction F. In the example illustrated in FIG. 3, a single post-treatment liquid head 6 is located at the right end of an array of ink heads 4. In another embodiment, multiple pretreatment liquid heads 5 or multiple post-treatment liquid heads 6 may be arranged. Although the carriage 3 may carry at least one pretreatment liquid head 5 and at least one post-treatment liquid head 6, the carriage 3 may carry none of the pretreatment liquid head 5 or the post-treatment liquid head 6 in another embodiment.
Note that a series of heads including the ink heads 4, the pretreatment liquid head 5, and the post-treatment liquid head 6 aligned in the main scanning direction S is referred to as an array of heads, or simply an array. A series of heads including the ink heads 4, the pretreatment liquid head 5, and the post-treatment liquid head 6 aligned in the feed direction F is referred to as a line of heads, or simply a line.
The pretreatment liquid head 5 ejects a pretreatment liquid for a predetermined pretreatment of the workpiece W. The pretreatment liquid is ejected from the pretreatment liquid head 5 to an area of the workpiece W on which no ink has been ejected from the ink heads 4. The pretreatment liquid is a noncolor-developing treatment liquid that develops no color on the workpiece W, and improves, for example, fixation of ink on the workpiece W or facilitates agglomeration of ink pigments. Examples of the pretreatment liquid include a treatment liquid of a solvent containing a bonding resin and a treatment liquid of a solvent containing a positively charged cationic resin.
The post-treatment liquid head 6 ejects a post-treatment liquid for a predetermined post-treatment of the workpiece W with ink applied. The post-treatment liquid is ejected from the post-treatment liquid head 6 to an area of the workpiece W on which ink has been ejected from the ink heads 4. The post-treatment liquid is also a noncolor-developing treatment liquid that develops no color on the workpiece W. The post-treatment liquid improves the fixation and the toughness (durability against rubbing or scratching) of an ink image printed on the workpiece W by the ink heads 4. Examples of the post-treatment liquid include a silicone treatment liquid. Note that the post-treatment liquid is different from the pretreatment liquid. More specifically, the post-treatment liquid and the pretreatment liquid contain different components.
The noncolor-developing treatment liquid refers to a liquid that is not perceptible as having developed a color to the naked eye when printed on a recording medium alone. The color includes colors with zero saturation, such as black, white, and gray. Although the noncolor-developing treatment liquid is basically a transparent liquid, a liter of treatment liquid in a liquid state may appear, for example, slightly white or another color. Such a faint color is not perceptible as having developed a color to the naked eye when printed on a recording medium alone. Note that, although a type of treatment liquid printed alone on a recording medium may cause a change such as adding gloss to the recording medium, such a change is not referred to as developing a color.
In the present embodiment, the pretreatment liquid and the post-treatment liquid may be ejected across substantially the entire surface of the workpiece W, or may be selectively ejected based on an image to be printed in the same manner as or in a similar manner to the ink.
Selective ejection of the pretreatment liquid and the post-treatment liquid will now be described. As described above, the pretreatment liquid, the ink, and the post-treatment liquid are ejected in this order on an area of the workpiece W on which colors are printed based on an image. In this case, the ink may have one color or multiple colors. For an area on which no color is printed, or in other words, an area on which no ink is ejected, no pretreatment liquid or no post-treatment liquid is basically ejected. Note that, to adjust the quality of an image to be printed or the texture of the workpiece W, areas on which the pretreatment liquid and the post-treatment liquid are selectively ejected may be partially different from an area on which ink is selectively ejected.
As illustrated in FIG. 3, the head support frame 31 includes openings 31H at positions of the heads. The head support frame 31 receives the ink heads 4, the pretreatment liquid head 5, and the post-treatment liquid head 6 fitted into the respective openings 31H. The nozzles on the lower end face of each of the heads 4, 5, and 6 are exposed through the corresponding opening 31H.
The multiple subtanks 7 are supported by the carriage 3 with a frame 70F (FIGs. 6 and 7, described later) above the heads 4, 5, and 6. The multiple subtanks 7 correspond to the respective heads 4, 5, and 6. Each of the subtanks 7 receives the ink or the treatment liquid from a main tank 91 and an intermediate tank 94 (described later) storing the ink or the treatment liquid, and supplies the ink or the treatment liquid to the corresponding head 4, 5, or 6. Each of the subtanks 7 is connected to the corresponding head 4, 5, or 6 with a pipe (not illustrated in FIG. 3).
The multiple subtanks 7 include a first supply subtank 71A to an eighth supply subtank 78A, a pretreatment supply subtank 7FA, and a post-treatment supply subtank 7RA. The multiple subtanks 7 also include a first collection subtank 71B to an eighth collection subtank 78B, a pretreatment collection subtank 7FB, and a post-treatment collection subtank 7RB. Note that the supply subtanks and the collection subtanks are illustrated as simple boxes for ease of explanation in FIG. 3. Their actual structures and shapes will be described in detail later.
The first supply subtank 71A (supply tank) and the first collection subtank 71B (collection tank) store yellow ink containing a pigment. The first supply subtank 71A stores the yellow ink (liquid) to be supplied to the first upstream ink head 41A and the first downstream ink head 41B (each referred to as an ejection head or a supply destination). The first collection subtank 71B stores the yellow ink collected from the first upstream ink head 41A and the first downstream ink head 41B. Note that part of the yellow ink is ejected from the first upstream ink head 41A and the first downstream ink head 41B onto the workpiece W as described above. In the same or a similar manner, the second supply subtank 72A stores magenta ink to be supplied to the second upstream ink head 42A and the second downstream ink head 42B. The second collection subtank 72B stores the magenta ink collected from the second upstream ink head 42A and the second downstream ink head 42B. The remaining third to eighth subtanks also have the same or similar structures and function as described above.
The pretreatment supply subtank 7FA stores the pretreatment liquid to be supplied to the pretreatment liquid head 5. The pretreatment collection subtank 7FB stores the pretreatment liquid collected from the pretreatment liquid head 5. The post-treatment supply subtank 7RA stores the post-treatment liquid to be supplied to the post-treatment liquid head 6. The post-treatment collection subtank 7RB stores the post-treatment liquid collected from the post-treatment liquid head 6.
In the present embodiment, as described above, the inkjet printer 1 is an all-in-one printer including three types of heads, or the ink heads 4, the pretreatment liquid head 5, and the post-treatment liquid head 6, mounted on the single carriage 3. The inkjet printer 1 can integrally perform the pretreatment liquid ejection and the post-treatment liquid ejection in an inkjet printing process on a textile in, for example, digital textile printing. This can simplify the textile printing process and reduce the size of textile printing apparatuses. With the subtanks 7 mounted on the carriage 3, the size of the apparatuses can be further reduced.
Note that the inkjet printer 1 according to the present embodiment performs the printing process on the workpiece W by serial printing. More specifically, for a wide workpiece W, the workpiece W cannot undergo printing while being fed continuously. With serial printing, the carriage 3 carrying the ink heads 4 of the respective colors repeatedly reciprocates in the main scanning direction S while the workpiece W is being intermittently fed in the feed direction F.
More specifically, the carriage 3 moving in an outgoing direction, which is one direction of the main scanning direction S, prints a strip image. During the main scanning in the outgoing direction, the feed of the workpiece W is stopped. The workpiece W on which the strip image has been printed is then fed forward in the feed direction F by a predetermined pitch. During the feed, the carriage 3 stays in the turn-back area 14 at the left end. After the workpiece W is fed forward, the carriage 3 turns back in a return direction opposite to the outgoing direction, as the timing belt 16 rotates in the reverse direction. The workpiece W is stopped. The carriage 3 then moves in the return direction and prints a subsequent strip image upstream from the strip image described above. The same or similar movement is repeated subsequently.

Circulation Path for Ink and Treatment Liquids

The flow of the ink and the treatment liquids in the inkjet printer 1 according to the present embodiment will now be described. Note that, although the flow of ink is described in detail below, the same or a similar structure is used for each of the treatment liquids. FIG. 4 is a schematic diagram illustrating the flow of ink near the first upstream ink head 41A and the first downstream ink head 41B in the present embodiment. FIG. 5 is a schematic diagram of a supply subtank and a collection subtank according to the present embodiment. Note that, in each of the figures, the lines connecting the components indicate pipes (tubes) for carrying a gas or a liquid.
In the present embodiment, a pressure is applied, with a gas (air), to each of the first supply subtank 71A to the post-treatment supply subtank 7RA (each also referred to as a supply tank) and the first collection subtank 71B to the post-treatment collection subtank 7RB (each also referred to as a collection tank) mounted on the carriage 3 in FIG. 3. This produces a difference in pressure (pressure difference) that causes a liquid (the ink, the pretreatment liquid, or the post-treatment liquid) to be supplied from each of the supply subtanks to the corresponding ink head 4, the pretreatment liquid head 5, or the post-treatment liquid head 6. The difference in pressure also causes the liquid to be collected into each of the collection subtanks from the corresponding head. The liquid collected into each of the collection subtanks is supplied to the corresponding supply subtank. In other words, a circulation path for each of the liquids is formed.
A circulation path including supply and collection paths for yellow ink to and from the first upstream ink head 41A and the first downstream ink head 41B will be described with reference to FIG. 4. Note that the same or a similar structure as in FIG. 4 is included in the ink heads for other colors.
The inkjet printer 1 further includes, on the carriage 3, filters 81, 82, 83, and 84, a circulation pump 85 (pump), a filter 86, a degasser 87, a supply electromagnetic valve 88, and a collection electromagnetic valve 89. The inkjet printer 1 further includes, outside the carriage 3 and on the apparatus frame 10 (FIG. 1), the main tank 91, a main-tank electromagnetic valve 92, a main supply pump 93, an intermediate tank 94, an intermediate-tank electromagnetic valve 95, an intermediate tank pump 96, a sensor 97, and a controller 100.
Yellow ink flowing from the first supply subtank 71A into an ink supply path QA through the supply electromagnetic valve 88 splits into a first ink path Q1 extending through the first upstream ink head 41A and a second ink path Q2 extending through the first downstream ink head 41B. The first upstream ink head 41A is connected to a first supply tube 711 and a first collection tube 713, and the first downstream ink head 41B is connected to a second supply tube 712 and a second collection tube 714 (refer to FIGs. 6 and 7).
The filter 81 is located upstream from the first upstream ink head 41A, and the filter 82 is located upstream from the first downstream ink head 41B. The filter 83 is located downstream from the first upstream ink head 41A, and the filter 84 is located downstream from the first downstream ink head 41B. These filters remove, for example, foreign matter or dust in ink. After the first upstream ink head 41A and the first downstream ink head 41B eject part of the yellow ink onto the workpiece W, the remaining ink is collected into the first collection subtank 71B through an ink collection path QB and the collection electromagnetic valve 89. The collected yellow ink is then supplied, by the circulation pump 85, to the first supply subtank 71A through an ink return path Q3 (return channel) extending from the first collection subtank 71B to the first supply subtank 71A.
The circulation pump 85 is a part of a circulation path Q for yellow ink extending from the first supply subtank 71A and back to the first supply subtank 71A through the first upstream ink head 41A, the first downstream ink head 41B, and the first collection subtank 71B as illustrated in FIG. 4. In the present embodiment, the circulation pump 85 is located on the ink return path Q3 to pump yellow ink from the first collection subtank 71B to the first supply subtank 71A.
The filter 86 is located on the ink return path Q3 to capture and remove, for example, foreign matter in ink to be supplied from the first collection subtank 71B to the first supply subtank 71A. The degasser 87 degasses ink (remove air bubbles) flowing through the ink return path Q3.
A heater 70H heats ink flowing through the ink return path Q3 before the ink is supplied to the first supply subtank 71A. Note that the detailed structure of the heater 70H will be described later. The ink to be supplied to the first supply subtank 71A is maintained at a temperature higher than or equal to a predetermined temperature. This maintains the temperature and viscosity of the ink flowing into the first upstream ink head 41A and the first downstream ink head 41B, thus maintaining stable performance for ink ejection from each of the heads.
Note that the supply electromagnetic valve 88 and the collection electromagnetic valve 89 are opened to respectively open the ink supply path QA and the ink collection path QB during normal printing.
The main tank 91 is mounted on the apparatus frame 10 in the inkjet printer 1 and stores yellow ink. Note that the same or similar main tanks 91 are also provided for other colors. The main-tank electromagnetic valve 92 is opened or closed to switch opening and closing of the channel from the main tank 91 to the intermediate tank 94. The main supply pump 93 operates to supply ink from the main tank 91 to the intermediate tank 94.
The intermediate tank 94 stores the yellow ink supplied from the main tank 91. The intermediate-tank electromagnetic valve 95 is opened or closed to switch opening and closing of an ink refill path Q4 extending from the intermediate tank 94 and merging into the ink return path Q3. The intermediate tank pump 96 operates to supply ink from the intermediate tank 94 to the first supply subtank 71A. The sensor 97 detects the amount of yellow ink remaining in the intermediate tank 94. Note that the main supply pump 93 operates to refill the intermediate tank 94 with ink supplied from the main tank 91 based on the detection results obtained by the sensor 97 indicating that the amount of ink in the intermediate tank 94 has fallen below a predetermined threshold. In contrast, the intermediate tank pump 96 operates to supply ink from the intermediate tank 94 to the first supply subtank 71A based on the detection results obtained by a capacitive sensor 71A1 and a capacitive sensor 71B1 (described later).
The controller 100 centrally controls the operation of the inkjet printer 1, and electrically controls each of the components illustrated in FIG. 4.
In one example as illustrated in FIG. 5, the first supply subtank 71A including a box-like tank body 710A stores yellow ink (liquid) with a supply-tank gas area SA and a supply-tank ink area SB defined inside. The supply-tank gas area SA is a space above a level L1 of the yellow ink in the first supply subtank 71A, and the supply-tank ink area SB is an area defined with the yellow ink. The supply-tank gas area SA communicates with a supply pressure channel P11. The supply pressure channel P11 communicates with a first pressure source P1 to regulate the pressure in the supply-tank gas area SA in the first supply subtank 71A and maintain a predetermined pressure. The supply pressure channel P11 includes a supply pneumatic coupling 751 (described later). The supply-tank ink area SB communicates with each of the ink supply path QA (the first ink path Q1 and the second ink path Q2), the ink return path Q3, and the ink refill path Q4.
The first supply subtank 71A includes the capacitive sensor 71A1 that can detect the level of yellow ink (the amount of ink) in the first supply subtank 71A.
In the same or a similar manner, the first collection subtank 71B including a box-like tank body 710B stores yellow ink with a collection-tank gas area SC and a collection-tank ink area SD defined inside. The collection-tank gas area SC is a space above a level L2 of the yellow ink in the first collection subtank 71B, and the collection-tank ink area SD is an area defined with the yellow ink. The collection-tank gas area SC communicates with a collection pressure channel P12. The collection pressure channel P12 communicates with a second pressure source P2 to regulate the pressure in the collection-tank gas area SC in the first collection subtank 71B and maintain a predetermined pressure. The collection pressure channel P12 includes a collection pneumatic coupling 752 (described later). The collection-tank ink area SD communicates with each of the ink collection path QB (the first ink path Q1 and the second ink path Q2) and the ink return path Q3.
The first collection subtank 71B includes the capacitive sensor 71B1 that can detect yellow ink in the first collection subtank 71B, and a capacitive sensor 71B2 that can detect bubbles of yellow ink above the level L2 of the yellow ink. The bubbles of ink correspond to foam or multiple bubbles. Note that the capacitive sensor 71B2 actually detects, based on the capacitance, a small amount of ink (liquid) forming films of multiple bubbles, rather than the gas in the bubbles.
In the present embodiment, the supply-tank gas area SA in the first supply subtank 71A is maintained at, for example, +2 kPa, and the collection-tank gas area SC in the first collection subtank 71B is maintained at, for example, -15 kPa. In this case, the tank body 710B of the first collection subtank 71B has a negative pressure with respect to the first upstream ink head 41A and the first downstream ink head 41B.
This generates a flow of yellow ink from the first supply subtank 71A to the first collection subtank 71B through the ink supply path QA (the first ink path Q1 and the second ink path Q2), each of the ink heads, and the ink collection path QB (the first ink path Q1 and the second ink path Q2) in FIG. 4. Note that both the supply-tank gas area SA and the collection-tank gas area SC may be maintained at a positive pressure higher than 0 kPa. Both the supply-tank gas area SA and the collection-tank gas area SC may also be maintained at a negative pressure lower than 0 kPa. The difference in pressure between the supply-tank gas area SA and the collection-tank gas area SC is 5 to 20 kPa. In any case, the first collection subtank 71B has a negative pressure with respect to each of the ink heads.
When the capacitive sensor 71B1 (FIG. 5) detects the level L2 of the ink in the first collection subtank 71B, the controller 100 causes the circulation pump 85 to operate. Part of the yellow ink in the first collection subtank 71B is then supplied to the first supply subtank 71A through the ink return path Q3. Note that the circulation pump 85 operates independently of whether the inkjet printer 1 is performing or stopping printing.
Additionally, when the controller 100 determines, based on the detection results obtained by the capacitive sensors 71A1 and 71B1, that the amount of yellow ink in both the first supply subtank 71A and the first collection subtank 71B has fallen below a predetermined threshold, the controller 100 opens the intermediate-tank electromagnetic valve 95 and causes the intermediate tank pump 96 to operate to refill the first supply subtank 71A with yellow ink supplied from the intermediate tank 94 through the ink refill path Q4 and the ink return path Q3. During this operation, the intermediate-tank electromagnetic valve 95 opens to adjust the maximum refill amount (refilling rate) for the first supply subtank 71A. When the sensor 97 detects an insufficient amount of yellow ink remaining in the intermediate tank 94, the controller 100 opens the main-tank electromagnetic valve 92 and causes the main supply pump 93 to operate to refill the intermediate tank 94 with yellow ink supplied from the main tank 91.

Structure of Tank Unit

The structure of each of the subtanks illustrated in FIGs. 3 to 5 will now be described in more detail. FIG. 6 is a perspective view of a tank unit 70 (liquid supply unit) according to the present embodiment of the present disclosure. FIG. 7 is a perspective view of the tank unit 70 as viewed in a direction opposite to the direction in FIG. 6. FIG. 8 is a perspective view of multiple tank units 70 attached to the carriage 3 in the present embodiment. Note that each of the heads is not illustrated in FIG. 8.
The tank unit 70 includes the first supply subtank 71A and the first collection subtank 71B, and is attachable to and detachable from the carriage 3 in the inkjet printer 1. The tank unit 70 is provided for each of the colors of ink, the pretreatment liquid, and the post-treatment liquid. As illustrated in FIGs. 6 and 7, the tank unit 70 includes the first supply subtank 71A, the first collection subtank 71B, the frame 70F (support) that supports these subtanks, the heater 70H described above, the circulation pump 85, the filter 86, the degasser 87, the supply electromagnetic valve 88, and the collection electromagnetic valve 89. Note that the tank unit 70 may or may not include all of these components.
The frame 70F supports the first supply subtank 71A and the first collection subtank 71B, and is detachably attachable to the carriage 3 (apparatus body) including the first upstream ink head 41A and the first downstream ink head 41B.
More specifically, the frame 70F includes a frame horizontal portion 70F1 (first support portion) and a frame rear portion 70F2 (second support portion). The frame horizontal portion 70F1 is a plate extending in a front-rear direction (horizontal direction) with a predetermined width in the lateral direction. The frame horizontal portion 70F1 supports the first supply subtank 71A and the first collection subtank 71B. More specifically, the frame 70F supports the first supply subtank 71A and the first collection subtank 71B to suspend (hang) the first supply subtank 71A and the first collection subtank 71B from the frame horizontal portion 70F1 of the frame 70F.
The frame rear portion 70F2 is a support portion different from the frame horizontal portion 70F1 and is fastened to the back frame 32 in the carriage 3. The frame rear portion 70F2 extends upward (in a vertical direction) from the rear end of the frame horizontal portion 70F1.
In the present embodiment, the tank unit 70 with the above structure allows the first supply subtank 71A and the first collection subtank 71B to include their support structure in upper portions of these subtanks. This can leave a space below the tank unit 70, allowing flexible positioning of the first supply tube 711 and the second supply tube 712 (supply tubes) for supplying ink to the corresponding ink heads, and the first collection tube 713 and the second collection tube 714 (collection tubes) for collecting ink from the corresponding ink heads.
The tank unit 70 with the above structure can stably supply and collect ink to and from each of the heads below the corresponding subtank in the carriage 3. The structure also allows effective use of the space in the carriage 3, thus reducing the size of the carriage 3.
The frame 70F includes, above the frame horizontal portion 70F1, a connector 750, the supply pneumatic coupling 751, the collection pneumatic coupling 752, a degasser vacuum coupling 753, and an ink coupling 754 (FIGs. 6 and 7). The connector 750 is used to supply power to the tank unit 70, and to transmit and receive various signals to and from the tank unit 70. The supply pneumatic coupling 751 is connected to the first pressure source P1 to set the supply-tank gas area SA in the first supply subtank 71A (FIG. 5) to a predetermined pressure. In the same or a similar manner, the collection pneumatic coupling 752 is connected to the second pressure source P2 to set the collection-tank gas area SC in the first collection subtank 71B (FIG. 5) to a predetermined pressure. The first pressure source P1 and the second pressure source P2 may share the same pressure source, and the pressure channels may be switched by, for example, an open-close valve.
The degasser vacuum coupling 753 is connected to a pressure path for evacuating the degasser 87. The ink coupling 754 is connected to the ink refill path Q4 in FIG. 4.
Referring to FIG. 5, the tank body 710A includes a connection hole P1H in its upper surface, and the tank body 710B includes a connection hole P2H in its upper surface. In other words, the connection hole P1H is located above the liquid level in the tank body 710A, and the connection hole P2H is located above the liquid level in the tank body 710B. The connection hole P1H communicates with the supply pneumatic coupling 751 with a tube (not illustrated), and the connection hole P2H communicates with the collection pneumatic coupling 752 with a tube (not illustrated). More specifically, the internal space of the tank body 710A communicates with the first pressure source P1 (FIG. 5) through the connection hole P1H and the supply pneumatic coupling 751, and the internal space of the tank body 710B communicates with the second pressure source P2 (FIG. 5) through the connection hole P2H and the collection pneumatic coupling 752.
In the present embodiment, the frame 70F that supports the first supply subtank 71A and the first collection subtank 71B is held by the back frame 32 in the carriage 3 (FIG. 2) in a cantilevered manner. More specifically, as illustrated in FIG. 6, the frame rear portion 70F2 of the frame 70F includes multiple threaded holes 70F3 and 70F4 (fastening portions) to be fastened to the back frame 32.
As illustrated in FIG. 8, a pair of screws 32H1 are attached to the back frame 32 in the carriage 3 for each of the tank units 70. A pair of screws 32H2 are also attached with the pair of screws 32H1 located between the pair of screws 32H2. Each of the screws is a known screw including a threaded portion and a head portion. To attach the tank unit 70 to the carriage 3, these screws are attached with the head portions of at least the screws 32H2 located apart from (or spaced from) the wall surface of the back frame 32 (wall).
As illustrated in FIG. 6, each of the threaded holes (fitting holes) in the frame rear portion 70F2 of the frame 70F is in the shape of a keyhole that is narrower in an upper portion. More specifically, each of the threaded holes includes a smaller-diameter portion having an inner diameter corresponding to the threaded portion of the screw, and a larger-diameter portion located below the smaller-diameter portion and having an inner diameter corresponding to the head portion of the screw.
To attach the tank unit 70 to the back frame 32, an operator first moves the tank unit 70 toward the back frame 32 in an attachment direction DS indicated by the arrow in FIG. 8. The tank unit 70 is placed to cause the head portions to enter the larger-diameter portions of the fitting holes. The operator then moves the tank unit 70 downward to cause the smaller-diameter portions of the fitting holes in the back frame 32 to receive the threaded portions of the screws. The operator then tightens the pair of screws 32H2 to fasten the tank unit 70 to the back frame 32. Note that the pair of screws 32H1 are intended to reduce the likelihood that the tank unit 70 slips off when attached, and may or may not be tightened firmly.
The frame rear portion 70F2 includes a protrusion 70F5 (rotation restrictor) below and spaced from the threaded holes described above (FIG. 6). The protrusion 70F5 is placed into a hole (not illustrated) in the back frame 32 in the carriage 3 when the tank unit 70 is attached. This structure restricts rotation of the frame 70F relative to the carriage 3 when the carriage 3 turns back in the main scanning direction S and is impacted. With the frame rear portion 70F2 fastened with the pair of left and right screws 32H2, such rotation can be further restricted.
In the present embodiment, as described above, the frame 70F in the tank unit 70 supports the first supply subtank 71A and the first collection subtank 71B, and is detachably attachable to the carriage 3.
This structure facilitates mounting of the tank unit 70 on the carriage 3 to supply ink to the first upstream ink head 41A and the first downstream ink head 41B and to collect ink from these heads.
The first supply tube 711 and the second supply tube 712 in FIGs. 6 and 7 communicate with the first supply subtank 71A to allow a flow of the ink, and are connectable to the first upstream ink head 41A and the first downstream ink head 41B when the frame 70F is attached to the carriage 3. In the same or a similar manner, the first collection tube 713 and the second collection tube 714 communicate with the first collection subtank 71B to allow a flow of the ink, and are connectable to the first upstream ink head 41A and the first downstream ink head 41B when the frame 70F is attached to the carriage 3.
The structure according to the present embodiment is compared with another example structure in which a supply tank and a collection tank are attachable to and detachable from an apparatus body and supply and collect ink to and from recording heads through ink channels included in an ink tank guide. Such a structure may have low maintainability for the components defining the ink supply path and the ink collection path. In contrast, in the present embodiment, the components defining the circulation path including the ink supply path and the ink collection path for the corresponding heads are included in the tank unit 70, as described above. This improves the maintainability for the channels. For example, when any of the channels in the tank unit 70 is clogged or broken, the tank unit 70 can be detached from the carriage 3 and can undergo maintenance easily outside the carriage 3. A spare tank unit 70 may be mounted on the carriage 3 to reduce the downtime of the inkjet printer 1.
In the present embodiment, in particular, the tank units 70 correspond to the heads for the respective colors mounted on the carriage 3 and are attachable to and detachable from the carriage 3 independently of one another. When the ink supply path or the ink collection path for a certain color of ink has a failure, the tank unit 70 corresponding to the color can be independently attached or detached, thus allowing easy and prompt maintenance. Note that the tank unit 70 for each of the pretreatment liquid and the post-treatment liquid also has the same or a similar structure.
In the present embodiment, the frame 70F supports the first supply subtank 71A and the first collection subtank 71B to hang the first supply subtank 71A and the first collection subtank 71B from the frame 70F. This allows effective use of the space below each of the subtanks. As illustrated in FIGs. 6 to 8, the portion of the back frame 32 in which each of the threaded holes is located is exposed on the front when the tank unit 70 is viewed from the front. Thus, the tank unit 70 can be mounted on the back frame 32 easily without each of the subtanks obstructing access to the screws 32H1 and 32H2 and areas around these screws.
In the present embodiment, the first supply subtank 71A and the first collection subtank 71B are located above and spaced from the corresponding ink heads when the frame 70F is attached to the carriage 3. The first supply tube 711, the second supply tube 712, the first collection tube 713, and the second collection tube 714 are located below the first supply subtank 71A and the first collection subtank 71B in the tank unit 70 to vertically connect the first supply subtank 71A and the first collection subtank 71B to the heads corresponding to these subtanks. This increases operability in arranging each of the channels after the tank unit 70 is mounted on the carriage 3. In particular, the support structure with which the frame 70F supports the subtanks is located in the upper portions of the subtanks, as described above. Each of the first supply tube 711 to the second collection tube 714 is thus less likely to interfere with the support structure, facilitating connection of each of the channels.
In the present embodiment, the frame 70F includes the frame horizontal portion 70F1 and the frame rear portion 70F2. The frame horizontal portion 70F1 can support the first supply subtank 71A and the first collection subtank 71B. The frame rear portion 70F2 is attachable to the back frame 32 in the carriage 3. Thus, the frame 70F supports each of the subtanks using a portion of the frame 70F, and is attached to the back frame 32 using another portion of the frame 70F. This facilitates mounting of the tank unit 70.
Further, in the present embodiment, the frame horizontal portion 70F1 extends in the horizontal direction, and the frame rear portion 70F2 extends in the vertical direction. This allows the frame horizontal portion 70F1 to stably support each of the subtanks, and also allows the frame rear portion 70F2 to be easily attached to the back frame 32.
In the present embodiment, the frame rear portion 70F2 includes the threaded holes 70F4 (fastening portions or openings) to be fastened to the back frame 32 in the carriage 3, and includes the protrusion 70F5 that restricts rotation of the frame 70F relative to the carriage 3. This reduces the likelihood that the tank unit 70 rotates under the acceleration (inertial force) acting on the tank unit 70 when the carriage 3 reciprocates in the main scanning direction.
In the present embodiment, the tank unit 70 can be temporarily fastened by engaging the threaded holes 70F3 and 70F4 in the frame rear portion 70F2 with the screws 32H1 and 32H2 on the back frame 32. The tank unit 70 can then be fully fastened to the carriage 3 by tightening the screws 32H2. This reduces the likelihood that the tank unit 70 slips off during the operation.
In the present embodiment, the tank unit 70 includes the filter 86. The filter 86 is located adjacent to the trailing ends (front ends) of the first supply subtank 71A and the first collection subtank 71B in the attachment direction DS (FIG. 8) in which the frame 70F is attached to the carriage 3 (FIGs. 6 and 7). This facilitates replacement of the filter 86 and viewing of the fill status in the filter in the tank unit 70 attached to the carriage 3. The structure also facilitates removal of air, ink, or foreign matter accumulating in the filter 86 associated with the use of the inkjet printer 1. Note that the filter 86 includes an ink outlet (not illustrated) in the lower surface with a cap (not illustrated). When the cap is removed, the ink can be discharged from the filter 86 under its weight.
In the present embodiment, the tank unit 70 includes the heater 70H. The heater 70H is located adjacent to the leading ends (far ends) of the first supply subtank 71A and the first collection subtank 71B in the attachment direction DS. This structure allows easier observation of the ink in each of the subtanks from the front of the carriage 3 than a structure in which the heater 70H is located adjacent to the front ends of the first supply subtank 71A and the first collection subtank 71B. When the tank unit 70 is attached to the carriage 3, the heater 70H is proximate to and faces the back frame 32. This allows dissipation of heat from the heater 70H through the back frame 32 when the heat insulation performance of the heater 70H is lowered. When the heater 70H is broken, the ink leaking from the heater 70H is less likely to spill onto the corresponding heads located below, ensuring the safety of the carriage 3. The heater 70H is thus located rearward from the corresponding heads as viewed in plan.
In the present embodiment, the tank unit 70 includes the circulation pump 85 supported by the heater 70H. The circulation pump 85, which is relatively heavy in the tank unit 70, is located in a lower portion of the tank unit 70 to lower the center of gravity of the tank unit 70. This increases the stability of the tank unit 70 in the carriage 3. Further, the structure reduces vibrations transmitted from the circulation pump 85 to each of the subtanks than a structure in which the circulation pump 85 is supported by the first supply subtank 71A, the first collection subtank 71B, or the frame 70F. This allows each of the capacitive sensors to detect the ink stably. Note that the heater 70H may be in close contact with the back frame 32. In this case, the heater 70H can release vibrations from the circulation pump 85 toward the back frame 32.
In the present embodiment, the tank unit 70 includes the degasser 87. The degasser 87 is located adjacent to the trailing ends (front ends) of the first supply subtank 71A and the first collection subtank 71B in the attachment direction DS. The first supply subtank 71A and the first collection subtank 71B are thus less likely to obstruct access to the degasser 87, thus facilitating maintenance of the degasser 87. When the degasser 87 is evacuated, in particular, the steam in the degasser 87 can be easily observed. The structure also facilitates removal of bubbles or water accumulating in the degasser 87 associated with the use of the inkjet printer 1.
In the present embodiment, the circulation pump 85 is located below the first supply subtank 71A and the first collection subtank 71B. This can lower the center of gravity of the tank unit 70 as described above, and thus increases the stability of the tank unit 70 in the carriage 3.
In the present embodiment, the tank unit 70 includes a handle 70G (grip) (FIGs. 6 and 7). The handle 70G is located above the frame 70F and is grippable by the operator when the frame 70F is attached to the carriage 3. The operator is less likely to directly touch functional components included in the tank unit 70, and can attach and detach the tank unit 70 to and from the carriage 3 safely.
In the present embodiment, the heater 70H is located upstream from the first supply subtank 71A in the flow of ink in the tank unit 70 (FIG. 4). The ink can be supplied to the first supply subtank 71A after being heated, and can thus be supplied to the corresponding heads at an intended temperature. This allows adjustment of the ink viscosity, thus maintaining stable performance for ink ejection.
Note that, in another embodiment, the heater 70H may be located upstream from the filter 86. More specifically, in FIG. 4, the heater 70H may be located between the circulation pump 85 and the filter 86. This structure allows the filter 86 to capture agglomerate in the ink heated by the heater 70H. Such agglomerate is thus less likely to flow into the first supply subtank 71A and the corresponding heads located downstream.
In another embodiment, the heater 70H may be located upstream from the degasser 87. More specifically, in FIG. 4, the heater 70H may be located between the filter 86 and the degasser 87. This structure allows the degasser 87 to efficiently remove bubbles after their rise is facilitated in the ink heated by the heater 70H.
In the present embodiment, the filter 86 is located upstream from the degasser 87. This structure allows agglomerate or other substances in the ink to be captured before the degassing process in the degasser 87. Such agglomerate or other substances are thus less likely to flow into the degasser 87, maintaining stable performance of the degasser 87.

Structure of Heater

The structure of the heater 70H included in the tank unit 70 will now be described in detail. FIG. 9 is a perspective view of the heater 70H in the present embodiment. FIG. 10 is an exploded perspective view of the heater 70H. In the present embodiment, as illustrated in FIG. 10, the heater 70H has a layered structure with seven plates.
More specifically, the heater 70H includes a front cover 701, a rear cover 702, a channel board 703, a front heater board 704, a rear heater board 705, a front heat insulator 706, and a rear heat insulator 707.
The front cover 701 and the rear cover 702 define the exterior of the heater 70H to protect the other plates from the front and the rear. The channel board 703 defines a channel for ink, which is a spiral channel as illustrated in FIG. 10. The channel board 703 includes an inlet and an outlet for ink in its lower end portion, and is exposed to the outside of the heater 70H as illustrated in FIG. 9.
The front heater board 704 and the rear heater board 705 sandwich the channel board 703 from the front and the rear. These heater boards define a part of the channel and also heat the ink in the channel. As illustrated in FIG. 10, the front heater board 704 includes four polyimide heaters 704A. Note that the rear heater board 705 also includes the same or similar polyimide heaters. The front heater board 704 and the rear heater board 705 are welded to the channel board 703 at multiple spot welds 704B. Note that the outer peripheries of the boards are joined together by fiber welding.
The front heat insulator 706 and the rear heat insulator 707 respectively cover the front heater board 704 and the rear heater board 705 from the front and the rear to reduce heat dissipation from the corresponding heaters. This can maintain high thermal efficiency of the heater 70H.
The ink flows from the degasser 87 in FIG. 4 into the heater 70H, in which the ink is heated by the front heater board 704 and the rear heater board 705 while flowing through the channel in the channel board 703 as indicated by the arrows in FIG. 10. The ink is then supplied to the first supply subtank 71A (FIG. 4). In the channel board 703, the incoming cold ink flows through an inner portion of the spiral channel, and the heated ink flows through an outer portion of the spiral channel to be discharged from the channel board 703. This allows heat exchange between the inner and outer inner peripheral portions, thus further increasing the heat exchange efficiency.
In the present embodiment, as described above, the heater 70H includes the channel board 703 including the channel for ink, and the pair of heater boards 704 and 705 sandwiching the channel board 703 to heat the ink flowing through the channel. This allows the ink to be heated efficiently while flowing through the circulation path in the tank unit 70 before being supplied to the corresponding heads.

Method for Mounting Tank Unit 70

The tank unit 70 on the carriage 3 described above may be mounted with the method described below. More specifically, the method described below is a method for mounting the tank unit 70 on the carriage 3 including the heads. The tank unit 70 includes the first supply subtank 71A that stores the liquid to be supplied to the heads and the first collection subtank 71B that stores the liquid collected from the heads.
The method includes attaching the first supply subtank 71A and the first collection subtank 71B to the frame 70F. The method further includes attaching the frame 70F to the carriage 3 with the first supply subtank 71A and the first collection subtank 71B attached to the frame 70F to allow the liquid to be supplied from the first supply subtank 71A to the heads and to be collected from the heads to the first collection subtank 71B.
This method facilitates mounting of the tank unit 70 on the carriage 3 to supply ink to the first upstream ink head 41A and the first downstream ink head 41B and to collect ink from these heads.
The method further includes connecting the first supply tube 711 and the second supply tube 712 to the corresponding heads and connecting the first collection tube 713 and the second collection tube 714 to the corresponding heads. The first supply tube 711 and the second supply tube 712 extend from the first supply subtank 71A. The first collection tube 713 and the second collection tube 714 extend from the first collection subtank 71B.
This method facilitates formation of the ink circulation path by easily mounting the tank unit 70 on the carriage 3, followed by connection of the supply tubes and the collection tubes to the corresponding heads.
The method further includes attaching the screws 32H2 including the threaded portions and the head portions to the back frame 32 included in the carriage 3 to cause the head portions to be located apart from the back frame 32 in a front direction. The method further includes placing the tank unit 70 to cause the head portions of the screws 32H2 to enter the larger-diameter portions of the threaded holes 70F4 (fitting holes) in the frame rear portion 70F2 of the frame 70F. Each of the threaded holes 70F4 includes the smaller-diameter portion having an inner diameter corresponding to the threaded portion of the screw 32H2, and the larger-diameter portion located below the smaller-diameter portion and having an inner diameter corresponding to the head portion. The method further includes moving the tank unit 70 downward to cause the smaller-diameter portions of the threaded holes 70F4 to receive the threaded portions of the screws 32H2. The method further includes tightening the screws 32H2 to fasten the tank unit 70 to the back frame 32.
This method facilitates mounting of the tank unit 70 on the carriage 3. In particular, the tank unit 70 can be temporarily fastened by engaging the threaded holes 70F4 in the frame rear portion 70F2 with the screws 32H2 on the back frame 32. The tank unit 70 can then be fully fastened to the carriage 3 by tightening the screws 32H2. This reduces the likelihood that the tank unit 70 slips off during the operation. Note that the screws 32H1 and the threaded holes 70F3 may be used to support and fix the tank unit 70 more stably as described above.
Note that, to detach the tank unit 70 from the carriage 3, the process described above can be reversed. More specifically, each of the screws is loosened, and the tank unit 70 is slightly lifted and then pulled frontward. This can detach the tank unit 70.
The method may further include placing the protrusion 70F5 on one of the frame 70F or the back frame 32 into a hole (not illustrated) in the other of the frame 70F or the back frame 32 to restrict rotation of the tank unit 70.
This method reduces the likelihood that the tank unit 70 rotates under the acceleration (inertial force) acting on the tank unit 70 when the carriage 3 reciprocates in the main scanning direction.
Note that the structure associated with the tank unit 70 described above further characterizes the above method.
The present disclosure is not limited to the above embodiments and may be implemented in the following forms.

(1) The ink heads 4 are not limited to those arranged in two arrays on the carriage 3. The ink heads 4 may be in a single array or in three or more arrays. The inkjet printer 1 is not limited to a printer configured to eject multiple colors of ink onto the workpiece W, and may be configured to eject a single color of ink. In the inkjet printer 1, the workpiece W may be supported at a predetermined print position, and the multiple heads held by the carriage 3 may eject liquids while moving in the main scanning direction and the subscanning direction. Each of the subtanks may supply and collect ink to and from a single head or three or more heads.
(2) In the above embodiments, the inkjet printer 1 may eliminate the pretreatment liquid head 5 that ejects the pretreatment liquid, the post-treatment liquid head 6 that ejects the post-treatment liquid, and any components associated with these heads.
(3) The multiple structures described in the above respective embodiments may be combined with one another to form an embodiment of the present invention.

REFERENCE SIGNS

1: inkjet printer (recording apparatus)
3: carriage
4: ink head (ejection head, supply destination)
41A: first upstream ink head
41B: first downstream ink head
5: pretreatment liquid head
6: post-treatment liquid head
7: subtank
70: tank unit (liquid supply unit)
70F: frame
70F1: frame horizontal portion
70F2: frame rear portion
70H: heater
710A, 710B: tank body
71A: first supply subtank (supply tank)
71A1, 71B1: capacitive sensor
71B: first collection subtank (collection tank)
Q: circulation path
Q1: first ink path
Q2: second ink path
Q3: ink return path (return channel)
Q4: ink refill path

Claims

A liquid supply unit, comprising:
a supply tank configured to store a liquid to be supplied to a supply destination;

a collection tank configured to store the liquid collected from the supply destination; and

a support configured to support the supply tank and the collection tank, the support being detachably attachable to an apparatus body including the supply destination.
The liquid supply unit according to claim 1, further comprising:
a supply tube communicating with the supply tank, the supply tube being connectable to the supply destination when the support is attached to the apparatus body; and

a collection tube communicating with the collection tank, the collection tube being connectable to the supply destination when the support is attached to the apparatus body.
The liquid supply unit according to claim 1, wherein
the support supports the supply tank and the collection tank to hang the supply tank and the collection tank from the support.
The liquid supply unit according to claim 2, wherein
the supply tank and the collection tank are located above and spaced from the supply destination when the support is attached to the apparatus body, and

the supply tube and the collection tube are located below the supply tank and the collection tank to vertically connect the supply tank and the collection tank to the supply destination.
The liquid supply unit according to claim 1, wherein
the support includes
a first support portion configured to support the supply tank and the collection tank, and

a second support portion attachable to the apparatus body.
The liquid supply unit according to claim 5, wherein
the first support portion extends in a horizontal direction, and the second support portion extends in a vertical direction.
The liquid supply unit according to claim 6, wherein
the second support portion includes
a fastening portion configured to be fastened to a carriage, the carriage being included in the apparatus body and being movable in a main scanning direction, and

a rotation restrictor spaced from the fastening portion to restrict rotation of the support relative to the carriage.
The liquid supply unit according to claim 7, wherein
the fastening portion includes an opening engageable with a screw on the carriage to be fastened to the carriage with the screw.
The liquid supply unit according to claim 1, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid; and

a filter located on the return channel to capture foreign matter in the liquid,

wherein the filter is located adjacent to trailing ends of the supply tank and the collection tank in an attachment direction in which the support is attached to the apparatus body.
The liquid supply unit according to claim 1, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid; and

a heater configured to heat the liquid flowing through the return channel,

wherein the heater is located adjacent to leading ends of the supply tank and the collection tank in an attachment direction in which the support is attached to the apparatus body.
The liquid supply unit according to claim 10, further comprising:
a pump located on the return channel to pump the liquid toward the supply tank,

wherein the pump is supported by the heater.
The liquid supply unit according to claim 1, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid; and

a degasser configured to degas the liquid flowing through the return channel,

wherein the degasser is located adjacent to trailing ends of the supply tank and the collection tank in an attachment direction in which the support is attached to the apparatus body.
The liquid supply unit according to claim 1, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid; and

a pump located on the return channel to pump the liquid toward the supply tank,

wherein the pump is located below the supply tank and the collection tank.
The liquid supply unit according to claim 1, further comprising:
a grip located above the support, the grip being grippable when the support is attached to the apparatus body.
The liquid supply unit according to claim 1, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid; and

a heater configured to heat the liquid flowing through the return channel,

wherein the heater is located upstream from the supply tank in the flow of the liquid.
The liquid supply unit according to claim 1 or claim 15, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid;

a heater configured to heat the liquid flowing through the return channel; and

a filter located on the return channel to capture foreign matter in the liquid,

wherein the heater is located upstream from the filter in the flow of the liquid.
The liquid supply unit according to claim 1 or claim 15, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid;

a heater configured to heat the liquid flowing through the return channel; and

a degasser configured to degas the liquid flowing through the return channel,

wherein the heater is located upstream from the degasser in the flow of the liquid.
The liquid supply unit according to claim 17, further comprising:
a filter located on the return channel to capture foreign matter in the liquid,

wherein the filter is located upstream from the degasser in the flow of the liquid.
The liquid supply unit according to claim 1, further comprising:
a return channel extending from the collection tank to the supply tank to allow a flow of the liquid; and

a heater configured to heat the liquid flowing through the return channel,

wherein the heater includes
a channel board including a channel for the liquid, and

a pair of heater boards sandwiching the channel board to heat the liquid flowing through the channel.
A recording apparatus, comprising:
the liquid supply unit according to claim 1; and

at least one ejection head being the supply destination configured to receive the liquid and eject the liquid onto a recording medium.
The recording apparatus according to claim 20, wherein
the at least one ejection head includes a plurality of ejection heads configured to eject different liquids, and

the recording apparatus includes a plurality of the liquid supply units configured to supply the respective different liquids to the plurality of ejection heads.
A method for mounting a liquid supply unit on an apparatus body including a supply destination, the liquid supply unit including a supply tank and a collection tank each configured to store a liquid, the method comprising:
attaching the supply tank and the collection tank to a support, and

attaching the support to the apparatus body with the supply tank and the collection tank attached to the support to allow the liquid to be supplied from the supply tank to the supply destination and to be collected from the supply destination to the collection tank.
The method according to claim 22, further comprising:
connecting each of a supply tube and a collection tube to the supply destination, the supply tube extending from the supply tank, the collection tube extending from the collection tank.
The method according to claim 22, wherein
attaching the support to the apparatus body includes
attaching a screw including a threaded portion and a head portion to a wall included in the apparatus body to cause the head portion to be located apart from the wall,

placing the liquid supply unit to cause the head portion to enter a larger-diameter portion of a fitting hole in the support, the fitting hole including a smaller-diameter portion having an inner diameter corresponding to the threaded portion and the larger-diameter portion located below the smaller-diameter portion and having an inner diameter corresponding to the head portion,

moving the liquid supply unit downward to cause the smaller-diameter portion of the fitting hole in the support to receive the threaded portion of the screw, and

tightening the screw to fasten the liquid supply unit to the wall.
The method according to claim 24, further comprising:
placing a protrusion on one of the support or the wall into a hole in the other of the support or the wall to restrict rotation of the liquid supply unit.