Head Unit and Inkjet Recording Apparatus

Abstract

To provide a head unit improved in assembling performance and reduced in cost, and an inkjet recording device.SOLUTION: A head unit 51 comprises a plurality of recording heads 52 and a liquid supply part 8. The liquid supply part 8 supplies the plurality of recording heads 52 with one or more kinds of liquid including ink. The liquid supply part 8 comprises a main body enclosure 81, an external connection port 83, and head connection ports 84. The main body enclosure 81 is positioned upper than ink discharge nozzles 521 of the plurality of recording heads 52, which has a common passage 85 through which liquid flows therein. The external connection port 83, provided in the main body enclosure 81, is communicated with one end part of the common passage 85 and is connected to an external liquid supply source, through which liquid flows. The head connection ports 84, provided in the main body enclosure 81, are communicated with the other end part side of the common passage 85 and are connected to the plurality of recording heads 52 respectively, through which liquid flows.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a head unit and an inkjet recording apparatus.

Background Art

[0002] A head unit mounted on an inkjet recording apparatus includes a recording head having a plurality of nozzles for ejecting ink onto a recording medium such as paper, and records an image on the recording medium. An example of such an inkjet recording apparatus is disclosed in Patent Document 1.

[0003] The conventional inkjet recording apparatus disclosed in Patent Document 1 includes an inkjet recording head capable of ejecting ink from a plurality of nozzles. The inkjet recording head is provided with first, second, third, fourth, and fifth ink flow paths for supplying ink to the plurality of nozzles. The proximal ends of the first flow path and the fourth flow path located at the upper end portion of the inkjet recording head are connected to an external ink supply path or an ink circulation path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the prior art, an ink supply path or an ink circulation path composed of piping such as a tube is connected to the proximal ends of the first flow path and the fourth flow path. When a plurality of inkjet recording heads are mounted for each color, the piping process such as tubes becomes complicated, and there is a problem in that the assemblability deteriorates. In addition, there is a concern that the cost increases due to an increase in the number and length of the tubes.

[0006] The present invention has been made in view of the above points, and an object thereof is to provide a head unit and an inkjet recording apparatus in which assemblability is improved and cost is reduced.

Means for Solving the Problems

[0007] To solve the above problems, the head unit of the present invention includes a plurality of recording heads and a liquid supply unit. The plurality of recording heads have a plurality of nozzles that eject ink onto a recording medium. The liquid supply unit supplies one or more liquids including the ink to the plurality of recording heads. The liquid supply unit includes a main body housing, an external connection port, and a head connection port. The main body housing is located above the nozzles of the plurality of recording heads and has a common flow path inside through which the liquid passes. The external connection port is provided in the main body housing, communicates with one end of the common flow path, and is connected to an external liquid supply source through which the liquid passes. The head connection port is provided in the main body housing, communicates with the other end side of the common flow path, and is connected to each of the plurality of recording heads through which the liquid passes.

Effects of the Invention

[0008] According to the configuration of the present invention, it is not necessary to connect a tube or the like for supplying a liquid such as ink to each of the plurality of recording heads. In other words, it is only necessary to connect the main body housing of the liquid supply unit to the plurality of recording heads, so piping processing such as tubes is unnecessary. Therefore, the assemblability of the head unit is improved, and cost reduction can be achieved.

Brief Description of the Drawings

[0009]

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following content.

[0011] FIG. 1 is a schematic cross-sectional front view of the inkjet recording apparatus 1 according to the embodiment. FIG. 2 is a top view of the recording unit 5 of the inkjet recording apparatus 1 of FIG. 1. The inkjet recording apparatus 1 is, for example, an inkjet recording type printer. As shown in FIGS. 1 and 2, the inkjet recording apparatus 1 includes an apparatus main body 2, a paper supply unit 3, a paper conveyance unit 4, a recording unit 5, a drying unit 6, and a control unit 7.

[0012] The paper supply unit 3 stores a plurality of sheets of paper (recording media) S, and separates and feeds out the sheets of paper S one by one during recording. The paper conveyance unit 4 conveys the sheet of paper S sent out from the paper supply unit 3 to the recording unit 5 and the drying unit 6, and further discharges the sheet of paper S after recording and drying to the paper discharge unit 21. When double-sided recording is performed, the paper conveyance unit 4 distributes the sheet of paper S after recording and drying on the first side to the reverse conveyance unit 44 by the branching unit 43, and further conveys the sheet of paper S with the conveyance direction switched and the front and back reversed back to the recording unit 5 and the drying unit 6 again.

[0013] The paper conveyance unit 4 includes a first belt conveyance unit 41 and a second belt conveyance unit 42. The first belt conveyance unit 41 has an endless first conveyance belt 411. The second belt conveyance unit 42 has an endless second conveyance belt 421. The first belt conveyance unit 41 and the second belt conveyance unit 42 adsorb and hold the sheet of paper S on the upper outer surface (upper surface) of each of the first conveyance belt 411 and the second conveyance belt 421 and convey it. The first belt conveyance unit 41 is disposed below the recording unit 5 and conveys the sheet of paper S. The second belt conveyance unit 42 is located on the downstream side in the paper conveyance direction with respect to the first belt conveyance unit 41, and is disposed in the drying unit 6 and conveys the sheet of paper S.

[0014] The recording unit 5 faces the sheet of paper S adsorbed and held on the upper surface of the first conveyance belt 411 and is disposed above the first conveyance belt 411 with a predetermined interval. As shown in FIG. 2, the recording unit 5 holds head units 51B, 51C, 51M, and 51Y corresponding to each of the four colors of black, cyan, magenta, and yellow. The head units 51B, 51C, 51M, and 51Y are juxtaposed along the paper conveyance direction Dc so that the longitudinal direction is parallel to the paper width direction Dw orthogonal to the paper conveyance direction Dc. Since the basic configurations of the four head units 51B, 51C, 51M, and 51Y are the same, in the following description, unless otherwise particularly limited, the identification symbols "B", "C", "M", and "Y" representing each color may be omitted.

[0015] Each of the color head units 51 has a line-type inkjet recording head 52. In each of the color head units 51, a plurality (for example, three (52a, 52b, 52c)) are arranged in a staggered manner along the paper width direction Dw.

[0016] The recording head 52 has a plurality of ink ejection nozzles 521 at its bottom. The plurality of ink ejection nozzles 521 are arranged side by side along the paper width direction Dw and can eject ink over the entire recording area on the paper S. That is, the recording head 52 has a plurality of ink ejection nozzles 521 for ejecting ink onto the paper S. The recording unit 5 sequentially ejects ink from the recording heads 52 of the four color head units 51B, 51C, 51M, and 51Y toward the paper S conveyed by the first conveyor belt 411, and records a full-color image or a monochrome image on the paper S.

[0017] The drying unit 6 is arranged on the downstream side in the paper conveyance direction with respect to the recording unit 5, and the second belt conveyance unit 42 is provided. The paper S on which the ink image is recorded in the recording unit 5 is dried while being adsorbed and held by the second conveyor belt 421 and conveyed in the drying unit 6.

[0018] The control unit 7 includes a CPU, a storage unit, and other electronic circuits and electronic components (all not shown). The CPU controls the operations of the respective components provided in the inkjet recording apparatus 1 based on the control programs and data stored in the storage unit, and performs processes related to the functions of the inkjet recording apparatus 1. Each of the paper supply unit 3, the paper conveyance unit 4, the recording unit 5, and the drying unit 6 receives individual commands from the control unit 7 and cooperates to record on the paper S. The storage unit is composed of a combination of a non-volatile storage device such as a program ROM (Read Only Memory) and a data ROM, and a volatile storage device such as a RAM (Random Access Memory).

[0019] Next, the configuration of the head unit 51 of the inkjet recording apparatus 1 will be further described with reference to FIGS. 3, 4, and 5 in addition to FIG. 2. FIGS. 3 and 4 are side and top views of the head unit 51 of the recording unit 5 in FIG. 2. FIG. 5 is a schematic side view of the head unit 51 in FIG. 3.

[0020] The head unit 51 includes a frame 53 and a liquid supply unit 8 in addition to three recording heads 52a, 52b, and 52c.

[0021] The frame 53 holds three recording heads 52a, 52b, and 52c. The three recording heads 52a, 52b, and 52c are arranged in a staggered pattern along the paper width direction Dw. The recording heads 52a and 52c are juxtaposed in the paper width direction Dw at the upstream portion of the head unit 51 in the paper conveyance direction Dc. The recording head 52b is located at the downstream portion of the head unit 51 in the paper conveyance direction Dc and is positioned between the recording heads 52a and 52c in the paper width direction Dw.

[0022] The liquid supply unit 8 overlaps the upper part of the recording heads 52 when viewed from the paper conveyance direction Dc and the paper width direction Dw. The liquid supply unit 8 is connected to the three recording heads 52a, 52b, and 52c. The liquid supply unit 8 supplies one or more liquids containing ink to the three recording heads 52a, 52b, and 52c. In the present embodiment, the liquid supply unit 8 supplies ink and a cleaning liquid for cleaning the ink ejection surface of the recording head 52 to the recording head 52. The liquid supply unit 8 has a main body housing 81 and a joint mechanism 82.

[0023] The main body housing 81 is located above the ink ejection nozzles 521 of the three recording heads 52a, 52b, and 52c. The main body housing 81 extends over the upper portions of the three recording heads 52a, 52b, and 52c in the paper width direction Dw.

[0024] The joint mechanism 82 is disposed below the main body housing 81. The joint mechanism 82 is fixed to the lower surface of the main body housing 81 and extends downward. The lower portion of the joint mechanism 82 is detachably connected to the recording head 52. The joint mechanism 82 has a liquid flow path through which liquid passes inside.

[0025] Three joint mechanisms 82 are provided for one recording head 52. That is, the liquid supply unit 8 has nine joint mechanisms 82. Two of the three joint mechanisms 82 for each recording head 52 are arranged on one end side in the paper width direction Dw of the recording head 52, and one is arranged on the other end side.

[0026] Subsequently, the configuration of the recording head 52 of the head unit 51 will be further described with reference to FIGS. 6, 7, and 8. FIG. 6 is a perspective view of the recording head 52 of the head unit 51 in FIG. 3. FIGS. 7 and 8 are a schematic side view and a schematic bottom view of the recording head 52 in FIG. 6. Since the three recording heads 52a, 52b, and 52c of each color have the same shape and the same configuration, the description of the identification symbols (a, b, c) will be omitted in the following description.

[0027] As shown in FIG. 7, the recording head 52 has an ink ejection surface F1 on its lower surface. As shown in FIG. 8, the ink ejection surface F1 has a nozzle region R in which a large number of ink ejection nozzles 521 are arranged. That is, a large number of ink ejection nozzles 521 open on the ink ejection surface F1. A water-repellent film (not shown) is formed on the ink ejection surface F1. For each of the four-color (black, cyan, magenta, yellow) recording heads 52, the four-color inks stored in an ink tank (liquid supply source) outside the head unit 51 are supplied individually for each color via the liquid supply unit 8.

[0028] Based on the control signal from the control unit 7, the recording head 52 discharges ink from the ink ejection nozzles 521 toward the paper S that is adsorbed and held on the conveyance surface of the first conveyance belt 411 and conveyed in response to the image data received from an external computer. As a result, a color image in which four colors of ink, black, cyan, magenta, and yellow, are overlaid is formed on the paper S on the first conveyance belt 411.

[0029] As shown in FIGS. 7 and 8, a cleaning liquid supply unit 9 is provided on one end side in the paper width direction Dw of the recording head 52. The cleaning liquid supply unit 9 is arranged adjacent to the recording head 52 on one end side in the paper width direction Dw of the recording head 52.

[0030] The cleaning liquid supply unit 9 has a cleaning liquid supply surface F2 on its lower surface. The cleaning liquid supply surface F2 is parallel to the ink ejection surface F1 and is adjacent to the ink ejection surface F1 along the paper width direction Dw. The adjacent region of the cleaning liquid supply surface F2 to the ink ejection surface F1 is configured in a thin plate shape and is arranged to overlap below the ink ejection surface F1. A water-repellent film (not shown) is formed on the cleaning liquid supply surface F2.

[0031] A large number of cleaning liquid supply ports 91 are opened on the cleaning liquid supply surface F2. The large number of cleaning liquid supply ports 91 are arranged in a staggered pattern along, for example, the paper conveyance direction Dc. The cleaning liquid supply ports 91 supply cleaning liquid to the cleaning liquid supply surface F2. The cleaning liquid is carried to the ink ejection surface F1 by a wiper (not shown) disposed below the recording head 52 and moving in the paper width direction Dw. That is, the cleaning liquid supply unit 9 supplies the cleaning liquid carried to the ink ejection surface F1.

[0032] The cleaning liquid is preferably a solution having a composition similar to that of ink without a coloring material. The cleaning liquid is a liquid composition composed of a solvent component and water, and a surfactant, a preservative, a fungicide, etc. are added as necessary. The cleaning liquid is excellent in cleaning ink and solubility of solidified ink.

[0033] Next, the configuration of the liquid supply unit 8 of the head unit 51 will be further described with reference to FIGS. 9, 10, 11, 12, and 13. FIGS. 9 and 10 are a perspective view and a bottom perspective view, respectively, of the liquid supply unit 8 of the head unit 51 in FIG. 4 as viewed from above. FIGS. 11 and 12 are an exploded perspective view and a bottom exploded perspective view, respectively, of the liquid supply unit 8 in FIG. 9 as viewed from above. FIG. 13 is a top view and a bottom view of the base member of the liquid supply unit 8 in FIG. 9, showing the liquid flow path. In each of these figures, the drawing of the joint mechanism 82 is omitted.

[0034] In addition to the main body housing 81 and the joint mechanism 82, the liquid supply unit 8 includes an external connection port 83 and a head connection port 84.

[0035] The main body housing 81 has a common flow path 85 through which liquid passes inside. In the present embodiment, the main body housing 81 has three common flow paths 85 (851, 852, 853). The common flow path 85 extends in the longitudinal direction (paper width direction Dw) of the main body housing 81.

[0036] In the present embodiment, ink and a cleaning liquid pass through the common flow path 85. Specifically, the three common flow paths 85 include a first ink flow path 851, a second ink flow path 852, and a cleaning liquid flow path 853. In the following description, unless otherwise particularly limited, the three liquid flow paths and their connection ports may be collectively referred to as the "common flow path 85", the "external connection port 83", and the "head connection port 84".

[0037] The external connection port 83 is provided on the main body housing 81. The external connection port 83 is disposed at one end in the longitudinal direction of the main body housing 81. The external connection port 83 communicates with one end of the common flow path 85. In the present embodiment, the liquid supply unit 8 has three external connection ports 83 (831, 832, 833) provided individually for the three common flow paths 85.

[0038] At the outer end of the external connection port 83, a pipe such as a tube extending from the outside is connected. The pipe is individually connected to three external connection ports 83 (831, 832, 833). The pipe is connected to an ink tank and a cleaning liquid tank (both liquid supply sources) outside the head unit 51. Ink or cleaning liquid passes through the external connection port 83.

[0039] The head connection port 84 is provided in the main body housing 81. The head connection port 84 is disposed on the lower surface of the main body housing 81. The head connection port 84 communicates with the other end of the common flow path 85. The head connection port 84 is provided for each of the three recording heads 52a, 52b, 52c for each of the three common flow paths 851, 852, 853.

[0040] Specifically, for the first ink flow path 851, three head connection ports 841a, 841b, 841c are provided individually for each of the three recording heads 52a, 52b, 52c. Similarly, for the second ink flow path 852, three head connection ports 842a, 842b, 842c are provided, and for the cleaning liquid flow path 853, three head connection ports 843a, 843b, 843c are provided. Below each of the nine head connection ports 84, a joint mechanism 82 (see FIGS. 5 and 6) is provided individually. Ink or cleaning liquid passes through the head connection port 84.

[0041] According to the above configuration, it is not necessary to connect a tube or the like for supplying a liquid such as ink or cleaning liquid to each of the three recording heads 52a, 52b, 52c. In other words, it is only necessary to connect the main body housing 81 of the liquid supply unit 8 to the three recording heads 52a, 52b, 52c, so piping processing such as tubes is unnecessary. Therefore, the assemblability of the head unit 51 is improved, and cost reduction can be achieved.

[0042] The main body housing 81 includes a base member 811, an upper lid member 812, and a lower lid member 813.

[0043] The base member 811 is positioned at the central portion in the vertical direction with respect to the upper lid member 812 and the lower lid member 813. In the present embodiment, three common flow paths 85 (851, 852, 853) are formed in the base member 811. The base member 811 has at least one common flow path 85 in each of the upper and lower portions.

[0044] Specifically, the first ink flow path 851 communicating with the external connection port 831 is formed in the upper portion of the base member 811.

[0045] The upstream portion and a part of the middle stream portion in the liquid flow direction of the second ink flow path 852 communicating with the external connection port 832 are formed in the lower portion of the base member 811. A part of the middle stream portion and the downstream portion in the liquid flow direction of the second ink flow path 852 are formed in the upper portion of the base member 811. The second ink flow path 852 has an inclined portion 852s extending from the lower portion to the upper portion of the base member 811. In the inclined portion 852s, the ink flows from the lower portion to the upper portion of the base member 811.

[0046] A part of the upstream portion in the liquid flow direction of the cleaning liquid flow path 853 communicating with the external connection port 833 is formed in the lower portion of the base member 811. A part of the upstream portion and the downstream portion in the liquid flow direction of the cleaning liquid flow path 853 are formed in the upper portion of the base member 811. The cleaning liquid flow path 853 has an inclined portion 853s extending from the lower portion to the upper portion of the base member 811. In the inclined portion 853s, the cleaning liquid flows from the lower portion to the upper portion of the base member 811.

[0047] All of the communication locations with each of the nine head connection ports 84 at the downstream ends of the liquid flow directions of the three common flow paths 85 are formed in the upper portion of the base member 811. That is, the liquid passing through the nine head connection ports 84 toward the recording head 52 flows downward from the common flow path 85 formed in the upper portion of the base member 811 and passes through the head connection ports 84.

[0048] Note that the upper part of the common flow path 85 formed on the upper part of the base member 811 is open. Similarly, the lower part of the common flow path 85 formed on the lower part of the base member 811 is open.

[0049] The upper cover member 812 is formed in a plate shape extending in the paper conveyance direction Dc and the paper width direction Dw, and is disposed adjacent to the upper surface of the base member 811. The upper cover member 812 covers the common flow path 85 in the upper part of the base member 811. Thereby, the common flow path 85 in the upper part of the base member 811 is sealed.

[0050] The lower cover member 813 is formed in a plate shape extending in the paper conveyance direction Dc and the paper width direction Dw, and is disposed adjacent to the lower surface of the base member 811. The lower cover member 813 covers the common flow path 85 in the lower part of the base member 811. Thereby, the common flow path 85 in the lower part of the base member 811 is sealed.

[0051] According to the above configuration, a plurality of common flow paths 85 can be easily formed with respect to the single main body housing 81 of the liquid supply unit 8. That is, it is possible to supply a plurality of liquids to the recording heads 52a, 52b, and 52c respectively using the single main body housing 81. According to this configuration, the assemblability of the head unit 51 is improved.

[0052] Further, the three common flow paths 85 include a first ink flow path 851 and a second ink flow path 852 through which ink passes, and a cleaning liquid flow path 853 through which a cleaning liquid passes. According to this configuration, the liquid supply unit 8 can supply ink and a cleaning liquid to each of the three recording heads 52a, 52b, and 52c. Therefore, when supplying ink and a cleaning liquid to the recording head 52, piping processing such as a tube becomes unnecessary, the assemblability is improved, and cost reduction can be achieved.

[0053] Note that the first ink flow path 851 may be used to supply ink from an external ink tank to the recording head 52, and the second ink flow path 852 may be used to circulate ink from the recording head 52 to the ink tank. According to this configuration, for example, when image recording can be realized with a small amount of ink, ink that is more than necessary can be returned to the external ink tank. Therefore, image recording can be performed efficiently.

[0054] As described above, the embodiments of the present invention have been explained, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the gist of the invention.

Industrial Applicability

[0055] The present invention can be used in a head unit and an inkjet recording apparatus.

Explanation of Signs

[0056] 1 Inkjet recording apparatus 5 Recording unit 8 Liquid supply unit 9 Cleaning liquid supply unit 51 Head unit 52, 52a, 52b, 52c Recording head 53 Frame 81 Main body housing 82 Joint mechanism 83 External connection port 84 Head connection port 85 Common flow path 521 Ink ejection nozzle 811 Base member 812 Upper lid member 813 Lower lid member 831, 832, 833 External connection port 841a, 841b, 841c Head connection port 842a, 842b, 842c Head connection port 843a, 843b, 843c Head connection port 851 First ink flow path (common flow path) 852 Second ink flow path (common flow path) 853 Cleaning liquid flow path (common flow path) S paper (recording medium)

Claims

1. A plurality of recording heads each having a plurality of nozzles for ejecting ink onto a recording medium, a liquid supply unit for supplying one or more liquids containing the ink to the plurality of recording heads, comprising: wherein the liquid supply unit has a main body housing located above the nozzles of the plurality of recording heads and having a common flow path inside which the liquid passes, an external connection port provided in the main body housing and communicating with one end of the common flow path and connected to an external liquid supply source through which the liquid passes, a head connection port provided in the main body housing and communicating with the other end side of the common flow path and connected to each of the plurality of recording heads through which the liquid passes, a base member in which a plurality of the common flow paths are formed and having at least one of the common flow paths in each of the upper and lower portions, an upper lid member covering the common flow path in the upper portion of the base member, a lower lid member covering the common flow path in the lower portion of the base member, comprising: wherein the plurality of common flow paths include an ink flow path through which the ink passes, a cleaning liquid flow path through which a cleaning liquid for cleaning the ink ejection surface of the recording head passes, and characterized in that it is a head unit.

2. The ink flow path is a first ink flow path for supplying the ink from the liquid supply source to the recording head, a second ink flow path for circulating the ink from the recording head to the liquid supply source, and characterized in that it is the head unit according to claim 1.

3. An inkjet recording apparatus characterized by comprising the head unit according to claim 1 or claim 2.

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