LIQUID FEEDING DEVICE AND INKJET RECORDING APPARATUS

INCORPORATION BY REFERENCE

This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2023-146354 filed Sep. 8, 2023, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The present disclosure relates to a liquid feeding device and an inkjet recording apparatus.

As a recording apparatus such as a printer or a copier, an inkjet recording apparatus is widely used, which ejects ink to a recording medium such as paper so as to record an image, because it can record a high definition image. In this inkjet recording apparatus, a pump conveys ink from an ink container that stores the ink to a recording head that ejects the ink to the recording medium. As this pump, a diaphragm pump is known.

SUMMARY

A liquid feeding device according to one aspect of the present disclosure includes a diaphragm pump, a suction unit, a discharge unit, and an optional unit. The diaphragm pump conveys liquid by reciprocating movement of a diaphragm. The suction unit includes a suction check valve configured to allow the liquid to flow only in a suction direction with respect to the diaphragm, and an inflow chamber into which the liquid flows through the suction check valve. The discharge unit includes a discharge check valve configured to allow the liquid to flow only in a discharge direction with respect to the diaphragm, and an outflow chamber from which the liquid entering from the inflow chamber flows out toward the discharge check valve. The optional unit is disposed between the suction unit and the discharge unit. The suction unit and the discharge unit are arranged in a stacking manner so that at least one said optional unit is sandwiched between them, and that the inflow chamber and the outflow chamber face the diaphragm on one side in a reciprocating direction of the diaphragm. The suction unit, the discharge unit, and the optional unit are attachable and detachable from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional front view of an inkjet recording apparatus according to one embodiment of the present disclosure.

FIG. 2 is a plan view of a recording unit and its vicinity of the inkjet recording apparatus illustrated in FIG. 1.

FIG. 3 is an explanatory diagram illustrating a structure of an ink feeding system and a control system of the recording unit and its vicinity of the inkjet recording apparatus illustrated in FIG. 1.

FIG. 4 is a front view of an ink feeding device illustrated in FIG. 3.

FIG. 5 is a top view of the ink feeding device illustrated in FIG. 3.

FIG. 6 is a side view of the ink feeding device illustrated in FIG. 3.

FIG. 7 is a perspective view of the ink feeding device illustrated in FIG. 3.

FIG. 8 is a vertical cross-sectional side view of the ink feeding device illustrated in FIG. 6.

FIG. 9 is a vertical cross-sectional side view of the ink feeding device illustrated in FIG. 8, and is a diagram illustrating an exploded state.

FIG. 10 is a vertical cross-sectional side view of a discharge unit of the ink feeding device illustrated in FIG. 8.

FIG. 11 is a vertical cross-sectional side view of a suction unit of the ink feeding device illustrated in FIG. 8.

FIG. 12 is a vertical cross-sectional side view of a filter unit of the ink feeding device illustrated in FIG. 8.

FIG. 13 is a top view of the filter unit illustrated in FIG. 12.

FIG. 14 is a top view of the filter unit illustrated in FIG. 12, and is a diagram illustrating a state where a filter is removed.

FIG. 15 is a top view of an optional unit according to Variation 1.

FIG. 16 is a top view of the optional unit according to Variation 2.

FIG. 17 is a perspective view of a plate-like member of the ink feeding device illustrated in FIG. 6.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present disclosure is described with reference to the drawings. Note that the present disclosure is not limited to the following description.

FIG. 1 is a schematic cross-sectional front view of an inkjet recording apparatus 1 of the embodiment. FIG. 2 is a plan view of a recording unit 5 and its vicinity of the inkjet recording apparatus 1 illustrated in FIG. 1. The inkjet recording apparatus 1 is an inkjet recording type printer, for example. As illustrated in FIGS. 1 and 2, the inkjet recording apparatus 1 includes an apparatus main body 2, a paper sheet supply unit 3, a paper sheet conveyance unit 4, the recording unit 5, a drying unit 6, a paper sheet discharge unit 7, and a control unit 8.

The paper sheet supply unit 3 is disposed in a lower part of the apparatus main body 2, for example. The paper sheet supply unit 3 stores a plurality of paper sheets (recording media) S, and it separates and sends out the paper sheets S one by one when recording.

The paper sheet conveyance unit 4 is disposed on a downstream side of the paper sheet supply unit 3 in a paper sheet conveying direction, so as to convey the paper sheet S sent out from the paper sheet supply unit 3. The paper sheet conveyance unit 4 conveys the paper sheet S to the recording unit 5 and the drying unit 6, and further discharges the paper sheet S after recording and drying to the paper sheet discharge unit 7. The paper sheet conveyance unit 4 includes a reverse conveyance unit 4r, for example. When performing two-side recording, the paper sheet conveyance unit 4 sends the paper sheet S after recording and drying on a first side to the reverse conveyance unit 4r, and switches the conveying direction so as to convey the paper sheet S whose front and back sides are reversed to the recording unit 5 and the drying unit 6 again.

The paper sheet conveyance unit 4 includes a first belt conveyance unit 41 and a second belt conveyance unit 42. The first belt conveyance unit 41 includes an endlessly formed first conveyor belt 411. The second belt conveyance unit 42 includes an endlessly formed second conveyor belt 421. The first belt conveyance unit 41 and the second belt conveyance unit 42 suck and hold the paper sheet S on upper side surfaces (upper surfaces) of the first conveyor belt 411 and the second conveyor belt 421, respectively, so as to convey the same. The first belt conveyance unit 41 is disposed below the recording unit 5 so as to convey the paper sheet S. The second belt conveyance unit 42 is disposed in the drying unit 6 on the downstream side of the first belt conveyance unit 41 in the paper sheet conveying direction, so as to convey the paper sheet S.

The recording unit 5 is disposed on the downstream side of the paper sheet supply unit 3 in the paper sheet conveying direction, so as to face the first belt conveyance unit 41. The recording unit 5 faces the paper sheet S sucked and held on the upper surface of the first conveyor belt 411 so as to be conveyed, and is disposed above the first conveyor belt 411 with a predetermined interval between them. In other words, the recording unit 5 faces the paper sheet S conveyed by the paper sheet conveyance unit 4.

As illustrated in FIG. 2, the recording unit 5 includes head units 51B, 51C, 51M, and 51Y corresponding to black, cyan, magenta, and yellow colors, respectively. The head units 51B, 51C, 51M, and 51Y are arranged side by side along a paper sheet conveying direction Dc, in such a manner that their longitudinal directions are parallel to a paper sheet width direction Dw perpendicular to the paper sheet conveying direction Dc. Note that the four head units 51B, 51C, 51M, and 51Y have the same basic structure, and the suffixes “B”, “C”, “M”, and “Y” indicating colors may be omitted in the following description, unless specification is necessary.

The head unit 51 of each color has a line type inkjet recording head 52. In the head unit 51 of each color, the recording head 52 includes a plurality of (e.g. three) heads 52a, 52b, and 52c arranged in a zigzag shape along the paper sheet width direction Dw.

The recording head 52 has a plurality of ink ejection nozzles 521 formed at the bottom part. The plurality of ink ejection nozzles 521 are arranged along the paper sheet width direction Dw, so that ink can be ejected over the entire recording region on the paper sheet S. In other words, the recording head 52 includes the plurality of ink ejection nozzles 521 that eject ink onto the paper sheet S. The recording unit 5 ejects ink sequentially from the recording heads 52 of the head units 51B, 51C, 51M, and 51Y of four colors, to the paper sheet S that is conveyed by the first conveyor belt 411, so as to record a full color image or a monochrome image on the paper sheet S.

The drying unit 6 is disposed on the downstream side of the recording unit 5 in the paper sheet conveying direction, and the second belt conveyance unit 42 is disposed in the drying unit 6. The paper sheet S on which an ink image is recorded in the recording unit 5 is sucked and held by the second conveyor belt 421 in the drying unit 6 so as to be conveyed, and the ink is dried during the conveyance. The paper sheet S after being dried is discharged to the paper sheet discharge unit 7.

The control unit 8 includes a CPU, a storage unit, and other electronic circuits and components (which are not shown). The CPU controls operations of individual components of the inkjet recording apparatus 1, on the basis of a control program and data stored in the storage unit, so as to perform processes related to functions of the inkjet recording apparatus 1. The paper sheet supply unit 3, the paper sheet conveyance unit 4, the recording unit 5, and the drying unit 6 each receive instructions separately from the control unit 8, and work in a synchronous manner so as to perform recording on the paper sheet S. The storage unit is constituted of a combination, for example, of a nonvolatile storage device such as a program read only memory (ROM) and a data ROM, and a volatile storage device such as a random access memory (RAM).

Next, a structure of the recording unit 5 and its vicinity is described with reference to FIG. 3. FIG. 3 is an explanatory diagram illustrating a structure of an ink feeding system and a control system of the recording unit 5 and its vicinity of the inkjet recording apparatus 1 illustrated in FIG. 1. The inkjet recording apparatus 1 includes an ink container 10, an ink feeding device (liquid feeding device) 20, a sub tank 30, and a head drive board 53.

The ink container 10 is disposed in an attachable and detachable manner with respect to the apparatus main body 2. The ink container 10 stores ink to be fed to the sub tank 30. The ink (liquid) in the ink container 10 is conveyed to the recording head 52 via the sub tank 30.

The ink feeding device 20 is disposed on the downstream side of the ink container 10 in the ink conveying direction. The ink feeding device 20 includes a diaphragm pump 21, and sucks the ink in the ink container 10 so as to discharge the ink toward the sub tank 30. The operation of the diaphragm pump 21 is controlled by the control unit 8. A detailed structure of the ink feeding device 20 will be described later.

The sub tank 30 stores the ink to be fed to the recording head 52. The sub tank 30 is equipped with an ink amount sensor (not shown). The control unit 8 controls the diaphragm pump 21 so as to control ink feeding amount from the ink container 10 to the sub tank 30, by driving time of the diaphragm pump 21. If the ink amount in the sub tank 30 detected by the ink amount sensor does not exceed a predetermined value after the driving time of the diaphragm pump 21 reaches a certain time, the control unit 8 determines that the ink amount in the ink container 10 is zero. Note that the sub tank 30 is managed in its ink amount at a constant water head difference with respect to the recording head 52.

The head drive board 53 is disposed adjacent to the recording head 52, and sends a drive signal to the recording head 52. The recording head 52 includes a driving element (not shown) of the ink ejection nozzle 521. The head drive board 53 sends a drive signal having a predetermined drive waveform and a predetermined drive voltage to the driving element of the ink ejection nozzle 521. The drive waveform of the driving element of the ink ejection nozzle 521 is prepared in advance according to a gradation value of a pixel (dot) of the image formed by ejected ink drops. The control unit 8 controls the head drive board 53 and can change the ejection speed of the ink ejected from the recording head 52. In this way, the control unit 8 controls operations of the recording head 52 so as to record an image on the paper sheet S.

Next, a schematic structure of the ink feeding device (liquid feeding device) 20 is described with reference to FIGS. 4 to 8, first. FIGS. 4, 5, 6, and 7 are respectively a front view, a top view, a side view, and a perspective view of the ink feeding device 20 illustrated in FIG. 3. FIG. 8 is a vertical cross-sectional side view of the ink feeding device 20 illustrated in FIG. 6.

Note that in the diagrams referred to in the following description, an arrow indicating a radial direction Dr of a motor 211 (an output shaft 211x) is appropriately shown, which corresponds to a reciprocating direction of a diaphragm 213 that will be described later. In a suction unit 22, in a discharge unit 23, and in filter units (optional units) 24A and 24B, a direction separating from the diaphragm 213 along the radial direction Dr (an upward direction in FIG. 8) is an ink flow direction. Specifically, with respect to the suction unit 22, the discharge unit 23, and the filter units (optional units) 24A and 24B, a lower side in FIG. 8 is an upstream side in the ink flow direction, while an upper side in FIG. 8 is a downstream side in the ink flow direction.

The ink feeding device 20 includes the diaphragm pump 21, the suction unit 22, the discharge unit 23, and the filter units (optional units) 24A and 24B.

The diaphragm pump 21 includes the motor 211 and a diaphragm mechanism unit 212. The diaphragm mechanism unit 212 houses the diaphragm 213. The diaphragm pump 21 allows the motor 211 to reciprocate the diaphragm 213, so as to convey the ink (liquid) by the reciprocating movement of the diaphragm 213.

The suction unit 22 is connected to the diaphragm mechanism unit 212 of the diaphragm pump 21, so as to be adjacent to the diaphragm 213. The suction unit 22 has a suction check valve 223 and an inflow chamber 222 provided to a suction casing 221. The inflow chamber 222 is communicated to the inside of the diaphragm mechanism unit 212. The ink externally flows into the inflow chamber 222 via the suction check valve 223. The suction check valve 223 allows the ink to flow only in a suction direction with respect to the diaphragm 213, i.e., in the direction flowing from the outside into the inflow chamber 222.

The discharge unit 23 is connected to the suction unit 22. In other words, the discharge unit 23 is disposed to the diaphragm mechanism unit 212 of the diaphragm pump 21 via the suction unit 22 and the filter units 24A and 24B. The discharge unit 23 has a discharge check valve 233 and an outflow chamber 232 provided to a discharge casing 231. The outflow chamber 232 is communicated to the inflow chamber 222 via the filter units 24A and 24B. The outflow chamber 232 allows the ink, which flows into it from the inflow chamber 222, to flow toward the discharge check valve 233. The discharge check valve 233 allows the ink to flow only in a discharge direction with respect to the diaphragm 213, i.e., in the direction flowing from the outflow chamber 232 to the outside.

The filter units 24A and 24B are disposed between the suction unit 22 and the discharge unit 23, in the radial direction Dr of the output shaft 211x of the motor 211 (the reciprocating direction of the diaphragm 213). The filter units 24A and 24B respectively have filters 241A and 241B that cover a flow cross section of the ink. The filter units 24A and 24B remove foreign objects included in the ink flowing from the suction unit 22 to the discharge unit 23, by the filters 241A and 241B.

Next, a detailed structure of the ink feeding device 20 is described with reference to FIGS. 9 to 12. FIG. 9 is a vertical cross-sectional side view of the ink feeding device 20 illustrated in FIG. 8, and is a diagram illustrating an exploded state. FIG. 10 is a vertical cross-sectional side view of the discharge unit 23 of the ink feeding device 20 illustrated in FIG. 8. FIG. 11 is a vertical cross-sectional side view of the suction unit 22 of the ink feeding device 20 illustrated in FIG. 8. FIG. 12 is a vertical cross-sectional side view of a filter unit 24 of the ink feeding device 20 illustrated in FIG. 8. Note that in FIG. 12, the suffix “A” or “B” of the filter unit 24 is omitted.

The diaphragm mechanism unit 212 of the diaphragm pump 21 is connected to a protruding part of the output shaft 211x of the motor 211. The diaphragm mechanism unit 212 includes an eccentric cam 214 and a coupling member 215 in addition to the diaphragm 213.

The eccentric cam 214 is fixed to the output shaft 211x of the motor 211. The eccentric cam 214 is formed in a circular shape extending outward in the radial direction Dr, viewed from an axial direction of the output shaft 211x, for example. The eccentric cam 214 is fixed to the output shaft 211x at a position shifted from the center of the circular periphery in the radial direction Dr. The motor 211 rotates the eccentric cam 214 about the axis of the output shaft 211x.

The coupling member 215 extends to the diaphragm 213 outside the output shaft 211x in the radial direction Dr. The coupling member 215 is coupled to the eccentric cam 214 and the diaphragm 213. In one end part of the coupling member 215, a hole 215h is formed in which an outer periphery part of the eccentric cam 214 penetrates in the axial direction of the output shaft 211x. The hole 215h of the coupling member 215 and the outer periphery part of the eccentric cam 214 are coupled in a smoothly slidable manner. When the motor 211 rotates the eccentric cam 214, the coupling member 215 reciprocates in the radial direction Dr of the output shaft 211x.

In addition, the diaphragm mechanism unit 212 has a diaphragm housing part 216. The diaphragm housing part 216 is positioned outside the coupling member 215 in the radial direction Dr of the output shaft 211x. The diaphragm housing part 216 is formed in a rectangular solid shape, i.e., in a rectangular shape viewed from the radial direction Dr of the output shaft 211x. The diaphragm housing part 216 has an opened side that faces the suction unit 22 and the discharge unit 23.

The diaphragm housing part 216 houses the diaphragm 213. The diaphragm 213 is fixed inside the diaphragm housing part 216. The diaphragm 213 is disposed to face the suction unit 22 and the discharge unit 23 via the opening of the diaphragm housing part 216.

The diaphragm 213 is an elastically deformable sheet-like member. The diaphragm 213 is formed in a circular shape extending in a direction perpendicular to the radial direction Dr of the output shaft 211x, for example. The outer periphery part of the diaphragm 213 is fixed to the diaphragm housing part 216. The center part of the diaphragm 213 is coupled to the other side of the coupling member 215, which is opposite to the one end part coupled to the eccentric cam 214.

When the motor 211 rotates the eccentric cam 214, the diaphragm 213 reciprocates in the radial direction Dr of the output shaft 211x via the coupling member 215. In this way, volume of the inflow chamber 222 of the suction unit 22 and the outflow chamber 232 of the discharge unit 23 increases and decreases. Thus, the diaphragm pump 21 conveys the ink by the reciprocating movement of the diaphragm 213.

The suction unit 22 is connected to the diaphragm housing part 216 so as to be adjacent to the diaphragm 213. The suction unit 22 includes the suction casing 221, the inflow chamber 222, and the suction check valve 223.

The suction casing 221 is formed in a rectangular solid shape, i.e., in a rectangular shape viewed from the radial direction Dr of the output shaft 211x of the motor 211. The external shape (the rectangular shape) of the suction casing 221 viewed from the radial direction Dr has the same size and shape as the external shape (the rectangular shape) of the diaphragm housing part 216 viewed from the radial direction Dr. The suction casing 221 is connected to the diaphragm housing part 216 in a sealed state for the ink inside.

The inflow chamber 222 is formed as an inside space of the suction casing 221. The inflow chamber 222 is formed in a cylindrical shape extending in the radial direction Dr of the output shaft 211x. The inflow chamber 222 has opened sides at one end part and the other end part in the radial direction Dr of the output shaft 211x, so that opening parts 222a and 222b are formed. The inflow chamber 222 is communicated to the diaphragm housing part 216 through the opening part 222a and faces the diaphragm 213. In addition, the inflow chamber 222 is communicated to the filter unit 24A via the opening part 222b. The ink flows externally into the inflow chamber 222 through the suction check valve 223.

In addition, in the inflow chamber 222, there are disposed a filter 225, an inner cylinder part 2222, a partition 2223, a filter holding part 2224, a filter facing part 2225, a plurality of flow holes 2226, and a plurality of protrusions 2227.

The inner cylinder part 2222 is disposed radially inside the inflow chamber 222 in the radial direction center part. In addition, the inner cylinder part 2222 is disposed in the inflow chamber 222 at a position on the downstream side of a position where the suction check valve 223 is disposed in the ink flow direction. The inner cylinder part 2222 is formed in a cylindrical shape extending in the radial direction Dr of the output shaft 211x of the motor 211 (the reciprocating direction of the diaphragm 213). The ink flows in the inner cylinder part 2222 along the radial direction Dr.

The partition 2223 is disposed at an upstream part of the inner cylinder part 2222 in the ink flow direction. The partition 2223 is formed in a flat circular plate shape extending in a flange shape outside the inner cylinder part 2222, in a direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). An inner edge part of the partition 2223 is connected to the upstream part of the outer periphery surface of the inner cylinder part 2222 in the ink flow direction. An outer edge part of the partition 2223 is connected to the inner periphery surface of the inflow chamber 222.

The filter holding part 2224 is formed at a downstream end of the inner cylinder part 2222 in the ink flow direction. The filter holding part 2224 is constituted as an annular flat surface facing the downstream side in the ink flow direction. An outer periphery part of the ink flow path of a filter 225 is attached to the filter holding part 2224. In this way, the filter holding part 2224 holds the outer periphery part of the ink flow path of the filter 225.

The filter facing part 2225 is positioned in the inner cylinder part 2222 on an inner side of the filter holding part 2224 in the ink flow path. The filter facing part 2225 is disposed apart from the filter 225 on the upstream side with respect to the downstream end in the ink flow direction of the inner cylinder part 2222. The filter facing part 2225 is formed in a flat circular plate shape extending in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213), along the ink flow cross section. The filter facing part 2225 faces the filter 225 in the ink flow direction.

The plurality of flow holes 2226 are formed in the filter facing part 2225. The plurality of flow holes 2226 are arranged in parallel at predetermined positions in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The plurality of flow holes 2226 penetrate the filter facing part 2225 in the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The ink flows through the plurality of flow holes 2226. In other words, for example, the ink flowing into the inflow chamber 222 through the suction check valve 223 passes through the plurality of flow holes 2226 and is directed to the filter 225.

The plurality of protrusions 2227 are formed on the filter facing part 2225. Specifically, the plurality of protrusions 2227 are formed on a surface of the filter facing part 2225 facing the filter 225 in the ink flow direction. The plurality of protrusions 2227 are arranged in parallel at predetermined positions in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The plurality of protrusions 2227 protrude toward the filter 225 in the ink flow direction, in the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The protrusion length of the protrusion 2227 is preferably a length such as to just contact the filter 225, but it may be shorter than the length to contact the filter 225.

The suction check valve 223 is attached to the suction casing 221. The suction check valve 223 is, for example, a ball type check valve having a valve body constituted of a ball. The suction check valve 223 includes a suction part 2231, a valve body housing part 2232, a liquid conduit 2233, a seal member 2234, a valve body 2235, and a biasing member 2236.

The suction part 2231 protrudes outside of the suction casing 221. The suction part 2231 is formed in a cylindrical shape and is connected to a liquid delivery tube (not shown) or the like in which the ink is conveyed. The suction unit 22 is connected to the ink container 10 (see FIG. 3) via the liquid delivery tube.

The valve body housing part 2232 is disposed continuously to the suction part 2231 on the downstream side of the suction part 2231 in the ink flow direction. The liquid conduit 2233 is disposed continuously to the valve body housing part 2232 on the downstream side of the valve body housing part 2232 in the ink flow direction. The valve body housing part 2232 and the liquid conduit 2233 are formed in a cylindrical shape extending in the ink flow direction. The liquid conduit 2233 is communicated to the inflow chamber 222.

The valve body housing part 2232 houses the seal member 2234, the valve body 2235, and the biasing member 2236.

The seal member 2234 is disposed adjacent to an inner periphery wall of the valve body housing part 2232 on the upstream side (the suction part 2231 side) of the valve body 2235 in the ink flow direction. The seal member 2234 is an O-ring made of an elastic material such as rubber, and its outer periphery part is tightly contacted with the inner periphery wall of the valve body housing part 2232. The seal member 2234 has an outer diameter that is larger than the inner diameter of the suction part 2231. The seal member 2234 has an inner diameter that is smaller than the outer diameter of the valve body 2235.

The valve body 2235 is constituted of a ball (a spherical shape), which can move in the valve body housing part 2232 in the ink flow direction. When the valve body 2235 moves to the upstream side in the ink flow direction, it contacts an inner periphery part of the seal member 2234 so as to close the suction part 2231. In this way, the suction check valve 223 allows the ink to flow only in the suction direction with respect to the diaphragm 213, while it prevents backflow of the ink.

The biasing member 2236 is disposed on the downstream side (the liquid conduit 2233 side) of the valve body 2235 in the ink flow direction. The biasing member 2236 is constituted of a helical compression spring, for example, and its helical shape has an axis extending along the center axis of the valve body housing part 2232.

An end part of the biasing member 2236 on the upstream side in the ink flow direction contacts the valve body 2235 as the ball. An end part of the biasing member 2236 on the downstream side in the ink flow direction contacts a wall surface of the valve body housing part 2232 facing the valve body 2235 at the downstream end in the ink flow direction. In this way, the biasing member 2236 biases the valve body 2235 in the direction to contact the seal member 2234, toward the upstream side in the ink flow direction. The suction check valve 223 allows the valve body 2235 to be contacted with the inner periphery part of the seal member 2234 by the biasing member 2236, and hence allows the ink to flow only in the suction direction with respect to the diaphragm 213, while it prevents backflow of the ink.

Note that when the diaphragm pump 21 works, its suction power allows the valve body 2235 to move to the downstream side in the ink flow direction against the biasing force of the biasing member 2236, and the ink flows from the outside of the suction unit 22 into the inflow chamber 222 through the suction check valve 223. When the diaphragm pump 21 is stopped, the valve body 2235 is moved by the biasing force of the biasing member 2236 to the upstream side in the ink flow direction, so as to contact the seal member 2234, and backflow of the ink can be prevented.

The discharge unit 23 is coupled to the filter unit 24B. As described above, the discharge unit 23 includes the discharge casing 231, the outflow chamber 232, and the discharge check valve 233.

The discharge casing 231 is formed in a substantially rectangular solid shape, i.e., in a rectangular shape viewed from the radial direction Dr of the output shaft 211x of the motor 211. The external shape (the rectangular shape) of the discharge casing 231 viewed from the radial direction Dr has the same size and shape as the external shape (the rectangular shape) of the diaphragm housing part 216, the suction casing 221, and the filter units 24A and 24B viewed from the radial direction Dr. The discharge casing 231 is connected to a filter case 242B described later of the filter unit 24B, in a sealed state for the ink inside.

The outflow chamber 232 is formed as an inside space of the discharge casing 231. The outflow chamber 232 is formed in a cylindrical shape extending in the radial direction Dr of the output shaft 211x. The outflow chamber 232 has an opened side at one end part in the radial direction Dr of the output shaft 211x, so that an opening part 232a is formed. The outflow chamber 232 is communicated to the filter unit 24B via the opening part 232a. The outflow chamber 232 allows the ink, which flows into it from the inflow chamber 222 of the suction unit 22 through the filter unit 24B, to flow out toward the discharge check valve 233.

In addition, a plurality of protrusions 2327 are disposed in the outflow chamber 232. In the outflow chamber 232, the plurality of protrusions 2327 are disposed on the upstream side in the ink flow direction of a position where the discharge check valve 233 is disposed. Specifically, the plurality of protrusions 2327 are formed on an end wall facing the upstream side in the ink flow direction in the outflow chamber 232. The plurality of protrusions 2327 are arranged in parallel at predetermined positions in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213).

The plurality of protrusions 2327 protrude toward the upstream side in the ink flow direction, in the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). Specifically, the plurality of protrusions 2327 protrude to the upstream side in the ink flow direction toward the filter 241 provided to the filter unit 24 neighboring in the radial direction Dr of the output shaft 211x. The protrusion length of the protrusion 2327 is preferably a length such as to just contact the filter 241, but it may be shorter than the length to contact the filter 241.

The discharge check valve 233 is attached to the discharge casing 231. The discharge check valve 233 is a ball type check valve whose valve body is constituted of a ball, for example. The discharge check valve 233 includes a discharge part 2331, a valve body housing part 2332, a liquid conduit 2333, a seal member 2334, a valve body 2335, and a biasing member 2336.

The discharge part 2331 protrudes outside of the discharge casing 231. The discharge part 2331 is formed in a cylindrical shape, and is connected to the liquid delivery tube (not shown) or the like in which the ink is conveyed. The discharge unit 23 is connected to the sub tank 30 (see FIG. 3) via the liquid delivery tube.

The valve body housing part 2332 is disposed continuously to the discharge part 2331 on the upstream side of the discharge part 2331 in the ink flow direction. The liquid conduit 2333 is disposed continuously to the valve body housing part 2332 on the upstream side of the valve body housing part 2332 in the ink flow direction. The valve body housing part 2332 and the liquid conduit 2333 are formed in a cylindrical shape extending in the ink flow direction. The liquid conduit 2333 is communicated to the outflow chamber 232.

The valve body housing part 2332 houses the seal member 2334, the valve body 2335, and the biasing member 2336.

The seal member 2334 is disposed adjacent to an inner periphery wall of the valve body housing part 2332 on the upstream side (the liquid conduit 2333 side) of the valve body 2335 in the ink flow direction. The seal member 2334 is an O-ring made of an elastic material such as rubber, and its outer periphery part is tightly contacted with the inner periphery wall of the valve body housing part 2332. The seal member 2334 has an outer diameter that is larger than the inner diameter of the liquid conduit 2333. The seal member 2334 has an inner diameter that is smaller than the outer diameter of the valve body 2335.

The valve body 2335 is constituted of a ball (a spherical shape), which can move in the valve body housing part 2332 in the ink flow direction. When the valve body 2335 moves to the upstream side in the ink flow direction, it contacts an inner periphery part of the seal member 2334 so as to close the liquid conduit 2333. In this way, the discharge check valve 233 allows the ink to flow only in the discharge direction with respect to the diaphragm 213, while it prevents backflow of the ink.

The biasing member 2336 is disposed on the downstream side (the discharge part 2331 side) of the valve body 2335 in the ink flow direction. The biasing member 2336 is constituted of a helical compression spring, for example, and its helical shape has an axis extending along the center axis of the valve body housing part 2332.

An end part of the biasing member 2336 on the upstream side in the ink flow direction contacts the valve body 2335 as the ball. An end part of the biasing member 2336 on the downstream side in the ink flow direction contacts a wall surface of the valve body housing part 2332 facing the valve body 2335 at the downstream end in the ink flow direction. In this way, the biasing member 2336 biases the valve body 2335 in the direction to contact the seal member 2334, toward the upstream side in the ink flow direction. The discharge check valve 233 allows the valve body 2335 to be contacted with the inner periphery part of the seal member 2334 by the biasing member 2336, and hence allows the ink to flow only in the discharge direction with respect to the diaphragm 213, while it prevents backflow of the ink.

Note that when the diaphragm pump 21 works, its discharge power allows the valve body 2335 to move to the downstream side in the ink flow direction against the biasing force of the biasing member 2336, and the ink flows from the inside of the outflow chamber 232 to the outside of the discharge unit 23 through the discharge check valve 233. When the diaphragm pump 21 is stopped, the valve body 2335 is moved by the biasing force of the biasing member 2336 to the upstream side in the ink flow direction, so as to contact the seal member 2334, and backflow of the ink can be prevented.

By using the ball type check valve, whose valve body is constituted of a ball, as the suction check valve 223 and the discharge check valve 233, backflow of the ink can be prevented with high accuracy. Therefore, it is possible to improve ink conveying performance by the ink feeding device 20.

In addition, the suction check valve 223 is attachable and detachable from the suction casing 221 of the suction unit 22. In addition, the discharge check valve 233 is attachable and detachable from the discharge casing 231 of the discharge unit 23. According to these structures, the structure of the check valve can be easily changed. For instance, if there is little possibility that a foreign object might mix into the ink, an umbrella valve or a duck bill valve may be used instead of the ball type check valve. In this way, it is possible to achieve lower cost of the ink feeding device 20.

In addition, as illustrated in FIG. 8, the suction unit 22 and the discharge unit 23 sandwich the filter units 24A and 24B between them, and are arranged in a stacking manner on one side of the diaphragm 213 in the reciprocating direction (on the upper side in the up and down direction in FIG. 8), with respect to the diaphragm pump 21. Specifically, the suction unit 22 and the discharge unit 23 are arranged in a stacking manner, so that the filter units 24A and 24B are sandwiched between them, and that the inflow chamber 222 and the outflow chamber 232 face the diaphragm 213 on the one side of the diaphragm 213 in the reciprocating direction. Further, the suction unit 22, the discharge unit 23, and the filter units 24A and 24B are attachable and detachable from each other.

Note that in this embodiment, the diaphragm pump 21 (the diaphragm housing part 216), the suction unit 22, the filter units 24A and 24B, and the discharge unit 23 are connected in this order, but the suction unit 22 and the discharge unit 23 may be exchanged. In this case, external shapes of the suction casing 221 and the discharge casing 231 should be changed so that the diaphragm pump 21 (the diaphragm housing part 216), the discharge unit 23, and the suction unit 22 can be connected in this order. Otherwise, the suction check valve 223 and the discharge check valve 233 may be exchanged.

In addition, it is sufficient that at least one of the filter units 24A and 24B is disposed as the optional unit.

According to the above structure, the optional units (the filter units 24A and 24B) are disposed on the upstream side in the ink flow direction of the discharge unit 23 that is disposed on the ink discharge side with respect to the diaphragm 213. The optional unit can be configured to perform various processes on the flowing ink. Therefore, it is possible to suppress deterioration in quality of the ink discharged from the diaphragm pump 21, or to increase quality of the ink.

In addition, the optional unit is the filter units 24A and 24B having the filters 241A and 241B that cover the ink flow cross section. According to this structure, foreign objects included in the ink flowing into the suction unit 22 can be removed by the filters 241A and 241B. In this way, the ink discharged from the discharge unit 23, i.e., from the ink feeding device 20 can be without foreign objects, and it is possible to suppress breakage of the recording head 52 or deterioration in image quality.

In addition, one of the suction unit 22 as the suction part of the ink and the discharge unit 23 as the discharge part of the ink, with respect to the diaphragm 213, is disposed adjacent to the diaphragm 213 so as to face the same, and the other is disposed to stack on the one. Further, either one of the suction unit 22 and the discharge unit 23 can be disposed adjacent to the diaphragm 213. In other words, positions of the suction part and the discharge part of the ink with respect to the diaphragm pump 21 can be arbitrarily changed, and it is possible to improve flexibility of the structure of the ink flow path. As a result, the ink feeding device 20 can support various structures of the inkjet recording apparatus 1 in which it is disposed, so that the ink can be efficiently conveyed.

The filter unit 24A includes the filter 241A and a filter case 242A. The filter unit 24B includes the filter 241B and the filter case 242B. The filter unit 24A is disposed on the upstream side of the filter unit 24B in the ink flow direction.

The filter units 24A and 24B have substantially the same basic structure except for coarseness of the filters 241A and 241B. Therefore, in the following description, the suffix “A” or “B” may be omitted unless specification is necessary.

The filter 241 is a sheet-like member extending in a direction perpendicular to the radial direction Dr of the output shaft 211x of the motor 211 (the reciprocating direction of the diaphragm 213), i.e., in a direction parallel to the diaphragm 213. The filter 241 is constituted of a metal mesh filter, for example. The filter 241 is held by a filter case 242, so as to cover the ink flow cross section.

The filters 241A and 241B have different coarseness values (mesh opening, aperture ratios). For instance, the filter 241B has a smaller coarseness value (mesh opening, aperture ratio) than the filter 241A disposed on the upstream side in the ink flow direction. In other words, the two filter units 24A and 24B respectively have the filters 241A and 241B whose coarseness decreases from the suction unit 22 side to the discharge unit 23 side.

According to the above structure, foreign objects of different sizes included in the ink can be removed sequentially by the two filter units 24A and 24B. In this way, by adjusting coarseness of the filters 241A and 241B, foreign objects included in the ink can be removed more effectively. In addition, it is possible to suppress clogging of the filters 241A and 241B.

In addition, specifically, the filter 241A has a smaller coarseness value (mesh opening, aperture ratio) than the filter 225 of the suction unit 22 disposed on the upstream side in the ink flow direction. In other words, the three filters 225, 241A, and 241B have coarseness values that decrease from the suction unit 22 side to the discharge unit 23 side.

According to the above structure, foreign objects of different sizes included in the ink can be removed sequentially by the three filters 225, 241A, and 241B. In this way, by adjusting coarseness of the filters 225, 241A, and 241B, it is possible to remove foreign objects included in the ink much more effectively. In addition, it is possible to suppress clogging of the filters 225, 241A, and 241B.

Further, a detailed structure of the filter unit 24 is described with reference to FIGS. 13 and 14 in addition to FIG. 12. FIG. 13 is a top view of the filter unit 24 illustrated in FIG. 12. FIG. 14 is a top view of the filter unit 24 illustrated in FIG. 12, and is a diagram illustrating a state where the filter 241 is removed. Note that in FIGS. 13 and 14, the suffix “A” or “B” of the filter unit 24 is omitted.

The filter case 242 of the filter unit 24 includes an outer cylinder part 2421, an inner cylinder part 2422, a flat plate part 2423, a filter holding part 2424, a filter facing part 2425, a plurality of flow holes 2426, and a plurality of protrusions 2427.

The outer cylinder part 2421 is disposed in the center part of the filter case 242. The inner cylinder part 2422 is disposed inside the outer cylinder part 2421 in the radial direction. The outer cylinder part 2421 and the inner cylinder part 2422 are formed in a cylindrical shape extending in the radial direction Dr of the output shaft 211x of the motor 211 (the reciprocating direction of the diaphragm 213). With respect to the ink flow direction in the filter unit 24, the inner cylinder part 2422 is disposed on an upstream part, while the outer cylinder part 2421 is disposed on a downstream part. The insides of the outer cylinder part 2421 and the inner cylinder part 2422 are communicated to each other at substantially the center part in the ink flow direction. The downstream part of the inner cylinder part 2422 in the ink flow direction protrudes to the downstream side in the outer cylinder part 2421. The ink flows along the radial direction Dr in the inner cylinder part 2422 and the outer cylinder part 2421 sequentially.

The flat plate part 2423 extends in a flange shape outside the outer cylinder part 2421 in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The external shape of the flat plate part 2423 is an rectangular shape viewed from the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The external shape (rectangular shape) of the flat plate part 2423 viewed from the radial direction Dr has the same size and shape as the external shape (rectangular shape) of the suction casing 221 or the discharge casing 231 viewed from the radial direction Dr. The flat plate part 2423 faces and contacts the flat plate part 2423 of the other filter unit 24, the suction casing 221, and the discharge casing 231 in the ink flow direction.

The filter holding part 2424 is formed at the downstream end of the inner cylinder part 2422 that protrudes to the downstream side in the ink flow direction in the outer cylinder part 2421. The filter holding part 2424 is formed as an annular flat surface facing the downstream side in the ink flow direction. The outer periphery part of the ink flow path of the filter 241 is attached to the filter holding part 2424. In this way, the filter holding part 2424 holds the outer periphery part of the ink flow path of the filter 241.

The filter facing part 2425 is positioned in the inner cylinder part 2422, on the inner side of the filter holding part 2424 in the ink flow path. The filter facing part 2425 is disposed apart from the filter 241 on the upstream side of the downstream end of the inner cylinder part 2422 in the ink flow direction. The filter facing part 2425 is formed in a flat circular plate shape extending along the ink flow cross section, i.e., in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The filter facing part 2425 faces the filter 241 in the ink flow direction.

The plurality of flow holes 2426 are formed in the filter facing part 2425. The plurality of flow holes 2426 are arranged in parallel at predetermined positions in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The plurality of flow holes 2426 penetrate the filter facing part 2425 in the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The ink flows through the plurality of flow holes 2426. In other words, for example, the ink, which reaches the filter unit 24 from the inflow chamber 222 of the suction unit 22, passes through the plurality of flow holes 2426 and is directed to the filter 241.

The plurality of protrusions 2427 are formed on the filter facing part 2425. Specifically, the plurality of protrusions 2427 are formed on a surface of the filter facing part 2425 facing the filter 241 in the ink flow direction, and on the opposite surface. The plurality of protrusions 2427 are arranged in parallel at predetermined positions in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213).

The plurality of protrusions 2427 protrude in the ink flow direction toward the filter 241 in the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). Specifically, the plurality of protrusions 2427, formed on the surface of the filter facing part 2425 facing the filter 241, protrude toward the filter 241. On the other hand, the plurality of protrusions 2427, formed on the opposite surface of the filter facing part 2425 opposite to the surface facing the filter 241, protrude toward the filter 241 provided to the other filter unit 24 neighboring in the radial direction Dr of the output shaft 211x, or toward the filter 225 provided to the suction unit 22. The protrusion length of the protrusion 2427 is preferably a length such as to just contact the filter 241 or 225, but it may be shorter than the length to contact the filter 241 or 225.

According to the above structure, the filter 241, which tends to displace in the ink flow direction by pressure when the ink flow, can be supported by the plurality of protrusions 2427. In this way, positional displacement or deformation of the filter 241 can be suppressed. Therefore, appropriate ink conveyance performance can be realized.

In addition, each of the plurality of protrusions 2427 formed on one side of the filter facing part 2425 and each of the plurality of protrusions 2427 formed on the other side of the same in the ink flow direction are disposed at the same position, in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). In addition, each of the plurality of protrusions 2227 formed on the suction unit 22 and each of the plurality of protrusions 2327 formed on the discharge unit 23 are also at the same position as each of the plurality of protrusions 2427 formed on the filter unit 24, in the direction perpendicular to the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). In other words, the plurality of protrusions 2427, 2227, and 2327 have distal end parts in the protrusion direction facing each other in the ink flow direction.

According to the above structure, two distal end parts out of the plurality of protrusions 2427, 2227, and 2327 can sandwich the filter 241 or 225 in the ink flow direction. In this way, the effect of suppressing positional displacement or deformation of the filter 241 or 225 can be enhanced. Therefore, appropriate ink conveyance performance can be maintained.

Next, variations of the ink feeding device 20 is described. FIG. 15 is a top view of the optional unit (a heater unit 24C) according to Variation 1. FIG. 16 is a top view of the optional unit (a heater unit 24D) according to Variation 2. Note that the variations have the same basic structure as the embodiment described above with reference to FIGS. 1 to 14, and the same component is denoted by the same numeral, symbol, or name, so that description thereof may be omitted.

The ink feeding device 20 may be equipped with the heater unit 24C or 24D illustrated in FIG. 15 or 16, as the optional unit.

As illustrated in FIG. 15, the heater unit 24C includes a heating section 246, for example, inside the inner cylinder part 2422. The heating section 246 is constituted of a coil bridging in the direction perpendicular to the radial direction Dr of the output shaft 211x of the motor 211 in the inner cylinder part 2422. The ink passing through the inner cylinder part 2422 of the heater unit 24C is heated by the heating section 246.

As illustrated in FIG. 16, the heater unit 24D includes a heating section 247, for example, inside the inner cylinder part 2422. The heating section 247 is constituted of a ceramic heater attached to the filter facing part 2425 in the inner cylinder part 2422. The ink passing through the inner cylinder part 2422 of the heater unit 24D is heated by the heating section 247.

As described above, the optional unit may be the heater unit 24C or 24D having the heating section 246 or 247 to heat the ink. According to this structure, the ink flowing into the suction unit 22 can be heated by the heating section 246 or 247. In this way, appropriate temperature management can be performed on the ink discharged from the discharge unit 23, i.e., the ink feeding device 20, and hence image quality can be improved.

In addition, as illustrated in FIGS. 8 and 9, the ink feeding device 20 includes three outer seal members 25A, 25B, and 25C. The three outer seal members 25A, 25B, and 25C are O-rings made of an elastic material such as rubber, for example.

The outer seal member 25A is disposed between the suction unit 22 and the filter unit 24A. Specifically, the outer seal member 25A is disposed between an inner edge part of the opening part 222b of the suction unit 22 and an outer edge part of the upstream part in the ink flow direction of the inner cylinder part 2422 of the filter unit 24A.

The outer seal member 25B is disposed between the filter unit 24A and the filter unit 24B. Specifically, the outer seal member 25B is disposed between an inner edge part of the downstream part in the ink flow direction of the outer cylinder part 2421 of the filter unit 24A and an outer edge part of the upstream part in the ink flow direction of the inner cylinder part 2422 of the filter unit 24B.

The outer seal member 25C is disposed between the filter unit 24B and the discharge unit 23. Specifically, outer seal member 25C is disposed between the inner edge part of the downstream part in the ink flow direction of the outer cylinder part 2421 of the filter unit 24B and the outer edge part of the opening part 232a of the discharge unit 23.

The three outer seal members 25A, 25B, and 25C are disposed between each of the suction unit 22, the discharge unit 23, and the filter units 24A and 24B, so as to prevent leakage of the ink to the outside. According to this structure, deterioration in conveyance performance of the ink can be suppressed, and further it is possible to prevent ink contamination in the inkjet recording apparatus 1.

In addition, as illustrated in FIGS. 6, 7, and 10, the discharge unit 23 has a plurality of unit positioning shafts 234. The unit positioning shafts 234 are disposed at four corners of the discharge casing 231 having the rectangular shape viewed from the radial direction Dr of the output shaft 211x of the motor 211 (see FIG. 7). In other words, the discharge unit 23 has the four unit positioning shafts 234.

The four unit positioning shafts 234 extend to the filter unit 24, the suction unit 22 and the diaphragm pump 21. In other words, the four unit positioning shafts 234 extend along the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213). The outer periphery of the distal end part of the unit positioning shaft 234 is provided with a thread.

In addition, as illustrated in FIGS. 12 and 13, the filter unit 24 has a plurality of unit positioning holes 245. The plurality of unit positioning holes 245 are formed at four corners of the filter unit 24 having a rectangular shape viewed from the radial direction Dr of the output shaft 211x of the motor 211. In other words, the filter unit 24 has the four unit positioning holes 245.

The four unit positioning holes 245 extend toward the discharge unit 23, the suction unit 22, and the diaphragm pump 21. In other words, the four unit positioning holes 245 extend along the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213), so as to penetrate the filter unit 24. Specifically, the four unit positioning holes 245 penetrate the flat plate part 2423 of the filter case 242. Note that the unit positioning holes 245 are not communicated to the inside of the outer cylinder part 2421 or the inside of the inner cylinder part 2422. The four unit positioning shafts 234 are inserted in the four unit positioning holes 245, respectively.

In addition, as illustrated in FIGS. 6 and 11, the suction unit 22 has a plurality of unit positioning holes 224. The unit positioning holes 224 are formed at four corners of the suction casing 221 having a rectangular shape viewed from the radial direction Dr of the output shaft 211x of the motor 211. In other words, the suction unit 22 has the four unit positioning holes 224.

The four unit positioning holes 224 extend toward the filter unit 24, the discharge unit 23 and the diaphragm pump 21. In other words, the four unit positioning holes 224 extend along the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213), so as to penetrate the suction casing 221. Note that the unit positioning holes 224 are not communicated to the inflow chamber 222. The four unit positioning shafts 234 are inserted in the four unit positioning holes 224, respectively.

In addition, as illustrated in FIG. 6, the diaphragm housing part 216 has a plurality of unit positioning holes 2161. The unit positioning holes 2161 are formed at four corners of the diaphragm housing part 216 having a rectangular shape viewed from the radial direction Dr of the output shaft 211x of the motor 211. In other words, the diaphragm housing part 216 has the four unit positioning holes 2161.

The four unit positioning holes 2161 extend toward the suction unit 22, the filter unit 24, and the discharge unit 23. In other words, the four unit positioning holes 2161 extend along the radial direction Dr of the output shaft 211x (the reciprocating direction of the diaphragm 213), so as to penetrate the diaphragm housing part 216. Note that the unit positioning holes 2161 are not communicated to the ink flowing region in the diaphragm housing part 216. The four unit positioning shafts 234 are inserted in the four unit positioning holes 2161, respectively.

The distal end parts of the four unit positioning shafts 234 protrude outward from one side (the lower side in FIG. 6) of the diaphragm housing part 216 opposite to the suction unit 22, the filter unit 24, and the discharge unit 23. The four unit positioning shafts 234 are inserted in four nuts 26 disposed on the side of the diaphragm housing part 216 opposite to the suction unit 22, the filter unit 24, and the discharge unit 23, so as to fasten the suction unit 22, the filter unit 24, the discharge unit 23, and the diaphragm housing part 216.

According to the above structure, it is possible to appropriately position the suction unit 22, the filter unit (optional unit) 24, and the discharge unit 23 with respect to the diaphragm pump 21 (the diaphragm housing part 216). Further, it is possible to prevent the ink from leaking from a connection part between each of the suction unit 22, the filter unit (optional unit) 24, the discharge unit 23, and the diaphragm housing part 216.

In addition, as illustrated in FIGS. 6 and 7, one side (the lower side in FIG. 6) of the diaphragm housing part 216 opposite to the suction unit 22, the filter unit 24, and the discharge unit 23 is provided with a plate-like member 27. The plate-like member 27 is disposed between the diaphragm housing part 216 and the four nuts 26. FIG. 17 is a perspective view of the plate-like member 27 of the ink feeding device 20 illustrated in FIG. 6.

The plate-like member 27 is formed in a C-shape viewed from the radial direction Dr of the output shaft 211x of the motor 211 (the reciprocating direction of the diaphragm 213). The external shape of the plate-like member 27 is a substantially rectangular shape viewed from the radial direction Dr of the output shaft 211x, which has the substantially same size and shape as the external shape (the rectangular shape) of the diaphragm housing part 216 viewed from the radial direction Dr. The plate-like member 27 is attached along the diaphragm housing part 216 by inserting the opened part of the C-shape in a plan view into the diaphragm mechanism unit 212.

The plate-like member 27 has a plurality of plate-like member positioning holes 271. The plate-like member positioning holes 271 are formed at four corners of the plate-like member 27 whose external shape viewed from the radial direction Dr of the output shaft 211x is the substantially rectangular shape. In other words, the plate-like member 27 has the four plate-like member positioning holes 271. The four plate-like member positioning holes 271 penetrate the plate-like member 27 in the radial direction Dr of the output shaft 211x (in the reciprocating direction of the diaphragm 213). The four unit positioning shafts 234 are inserted in the four plate-like member positioning holes 271, respectively.

By disposing the plate-like member 27 adjacent to the diaphragm housing part 216, fastening strength of the suction unit 22, the filter unit 24, the discharge unit 23, and the diaphragm housing part 216 by the unit positioning shafts 234 can be enhanced. Therefore, it is possible to effectively prevent the ink from leaking from the connection part between each of the suction unit 22, the filter unit 24, the discharge unit 23, and the diaphragm housing part 216.

Although the embodiment of the present disclosure is described above, the scope of the present disclosure is not limited to this, but can be variously modified for implementation within the scope of the present disclosure without deviating from the spirit thereof.

For instance, in the embodiment described above, the ink feeding device 20 includes the two filter units 24A and 24B as optional units, but this structure is not a limitation. Three or more optional units may be disposed. For instance, the ink feeding device 20 may further include one of the heater units 24C and 24D in addition to the two filter units 24A and 24B.

LIQUID FEEDING DEVICE AND INKJET RECORDING APPARATUS

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CPC

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