Patent Grant
9731510
1. Field of the Invention
This invention relates to an inkjet printing apparatus with a plurality of inkjet heads.
2. Description of the Related Art
A conventional inkjet printing apparatus having an inkjet head with many inkjet nozzles performs cleaning to the inkjet head by suction (suction purge) so as to eliminate printing failure, so-called nozzle clogging, resulting from partial clogging of the inkjet nozzles.
For instance, Japanese Patent Publication No. 2008-213216 discloses an inkjet recorder. The inkjet recorder includes caps covering ejection port groups (an inkjet head) individually, and a pump supplying ink from the ejection ports (inkjet nozzles) into the caps. The inkjet recorder further includes a connection channel connecting the caps to the pumps, respectively, and on/off valves provided on the channel individually. In the inkjet recorder, the on/off valves on the connection channel in communication with each of the caps of the group of ejection ports (inkjet heads) are selectively opened, whereby suction purge can be achieved in which only a cap covering the inkjet nozzle with no ink being ejected therefrom is connected to the pump to be sucked individually.
Another inkjet printing apparatus has also been proposed. The inkjet printing apparatus includes a cleaning mechanism that allows overall suction for sucking collectively a plurality of inkjet heads and individual suction for sucking every inkjet head individually. See International Publication WO2007/058139. The cleaning mechanism includes an individual suction cap that connects one cap, selected from caps covering a plurality of inkjet heads, to a pump via a tube; the caps connected to the pump via a tube branched to the caps; a first on/off valve switching suction of the plurality of caps simultaneously; and a second on/off valve switching suction of only the individual suction cap. Overall suction is performed while the plurality of inkjet heads are all covered with the caps to open the first and second on/off valves. Individual suction is performed while only one inkjet head is covered with the individual suction cap to close the first on/off valve and to open the second on/off valve. This allows individual suction for the inkjet head to be sucked.
The apparatus disclosed in Japanese Patent Publication No. 2008-213216 has a drawback as under. That is, many electromagnetic on/off valves corresponding to the number of caps have to be disposed, resulting in an enlarged apparatus and increased production costs. The apparatus has another drawback as under. That is, many electromagnetic on/off valves are driven, resulting in increased power consumption and running costs.
Moreover, the apparatus of WO2007/058139 performs cleaning to every inkjet unit having a plurality of inkjet heads being arranged in one direction. Consequently, when individual suction is performed to the inkjet heads, it takes longer time to move the inkjet unit to align the inkjet heads with the individual suction cap depending on arrangement of the inkjet heads to be sucked in the inkjet unit. This causes a drawback that longer time is required for cleaning the inkjet heads.
In order to solve the above-mentioned drawbacks, one object of this invention is to provide an inkjet printing apparatus with a simple construction that allows reduction in ink consumption and rapid cleaning of inkjet heads.
This invention is constituted as stated below to achieve the above object. One example of this invention discloses an inkjet printing apparatus with a plurality of inkjet heads having a plurality of inkjet nozzles being arranged in a row; a plurality of caps for the plurality of inkjet heads respectively; a plurality of lines in communication with the plurality of caps respectively; and a suction device sucking ink from the plurality of inkjet nozzles via the plurality of caps and the plurality of lines. The inkjet printing apparatus includes a draw-off port connecting to the suction device; a switching section having an internal communication path in communication with the draw-off port and being supported rotatably while being connected to a driving device; a housing accommodating the switching section and having external suction ports and an internal suction port being disposed at an equal distance from the center of rotation of the switching section, the external suction ports being connectable to the plurality of lines, the internal suction port being connected to a suction path for sucking an interior of the housing; further including a connection switching device for selectively connecting the suction port to the suction device by rotating the switching section to a position where the communication path is brought into communication with any of the plurality of external suction ports.
The example of this invention includes the connection switching device for selectively connecting any of the plurality of external suction ports to the suction device by rotating the switching section in the housing having the external suction ports and the internal suction port being disposed at an equal distance from the center of rotation of the switching section. Here, the external suction ports are connectable to the plurality of lines, and the internal suction port is connected the suction path for sucking the interior of the housing. When the switching section is connected to any of the external suction ports, ink is sucked from any of the plurality of inkjet nozzles. When the switching section is connected to the internal suction port, the interior of the housing is sucked, whereby ink is sucked from all the inkjet nozzles. Consequently, reduction in ink consumption due to suction purge of the inkjet head in no need of suction purge can be achieved. Moreover, rapid cleaning can be performed to the plurality of inkjet heads selectively.
In addition, the housing in the example of this invention preferably includes the draw-off port of the suction path on the bottom of the housing, the suction path sucking the interior of the housing.
In addition, the housing in the example of this invention preferably includes the plurality of external suction ports arranged radially.
In addition, the housing in the example of this invention preferably includes the plurality of external suction ports arranged coaxially.
In addition, the housing in the example of this invention preferably includes the suction path sucking the interior of the housing.
In addition, the switching section in the example of this invention has an L-shape. A first end of the switching section rotates by the driving device, whereas a second end thereof is communicated with each of the plurality of external suction ports. Such a construction is preferable.
In addition, the switching section in the example of this invention has a crank shape. A first end of the switching section rotates by the driving device, whereas a second end thereof is communicated with each of the plurality of external suction ports. Such a construction is preferable.
In addition, the housing in the example of this invention preferably includes a closed bearing at the center of rotation of the switching section.
In addition, the plurality of inkjet heads is provided for every single-color ink.
The inkjet printing apparatus in the example of this invention includes the connection switching device for selectively connecting any of the plurality of external suction ports to the suction device by rotating the switching section in the housing having the external suction ports and the internal suction port being disposed at an equal distance from the center of rotation of the switching section. Here, the external suction ports are connectable to the plurality of lines, and the internal suction port connects the suction path for sucking the interior of the housing. When the switching section is connected to any of the external suction ports, ink is sucked from any of the plurality of inkjet nozzles. When the switching section is connected to the internal suction port, the interior of the housing is sucked, whereby ink is sucked from all the inkjet nozzles. Consequently, reduction in ink consumption due to suction purge of the inkjet head in no need of suction purge can be achieved. Moreover, rapid cleaning can be performed to the plurality of inkjet heads selectively.
Moreover, the housing includes inside thereof the draw-off port of the suction path sucking the interior of the housing. This ensures suction of ink accumulated in the interior of the housing.
Moreover, the housing has the suction path formed therein for sucking the interior of the housing. This achieves a compact housing.
Description will be given hereinafter of examples of this invention with reference to the drawings.
The controller 1 controls the inkjet printing apparatus 1 entirely. The controller 1 controls transportation of a sheet 9 by the transporting section 2, ejection of ink onto the sheet 9 by the ejector 3 or cleaning in the ejector 3, drying of the sheet 9 with the ink ejected thereon by the drying section 4, imaging of a printing image on the sheet 9 by the inspecting section 5. Such control achieves printing onto the sheet 9 by the inkjet printing apparatus 100.
The transporting section 2 transports the sheet 9 in the inkjet printing apparatus 100. The transporting section 2 includes a sheet accommodating section 20, a drive roller 21, and a support roller 22.
The sheet accommodating section 20 accommodates the sheet 9 as a roll sheet to be printed. A sheet accommodating section 20a accommodates the printing sheet 9 prior to printing, and a sheet accommodating section 20b accommodates the sheet 9 subsequent to the printing.
The sheet 9 fed out from the sheet accommodating section 20a is transported to the ejector 3, the drying section 4, and the inspecting section 5 with drive rollers 21a and 21b while being supported by the support roller 22. Then the sheet 9 is wound up in the sheet accommodating section 20b.
The ejector 3 receives ink from an ink tank, not shown. The ejector 3 ejects the ink in response to drive signals generated by the controller 1 in accordance with image information, thereby performing printing onto the sheet 9.
The ejector 3 includes a plurality of inkjet nozzle groups 30k, 30c, 30m, and 30y. The inkjet nozzle groups 30k, 30c, 30m, and 30y extend perpendicularly relative to a transport direction of the sheet 9. Arrangement of many nozzles in a row achieves a width of ejection more than a width of the sheet 9 to be transported. Such a construction of the ejector 3 achieves printing by one-time ejection without performing reciprocated scanning in a width direction of the sheet 9 to be transported.
Here, the number of inkjet nozzle groups in the ejector 3 is limited to four, but may be one for single-color ejection. Moreover, the number of inkjet nozzle groups may be five or more for additional special-color ejection.
The drying section 4 heats the sheet 9 subsequent to printing by the ejector 3 with use of a heater, a dryer, and the like, to evaporate solvent of ink (mainly, water). Consequently, the ink is fixed.
The drying section 4 includes a construction of oscillating radiation. Consequently, when radiation-curable ink, such as an ultraviolet-curable ink, is ejected from the ejector 3, the ink is fixed (cured) on the sheet 9.
The inspecting section 5 takes printing images so as to determine whether or not the controller 1 performs printing onto the sheet 9 satisfactorily. The inspecting section 5 takes a printing image 5 printed on the sheet 9 to be transported with use of a CCD line sensor or a CCD camera, and then transmits information on the image to the controller 1. The controller 1 compares the image information used for ink ejection with photographic information to determine an ejection failure in the ejector 3. This enables to determine whether or not the printing is performed satisfactorily.
Here, the ejection failure is, for example, no-ink ejection from the nozzle, failure in spraying of ink droplets, or failure in size of ink droplets. When the controller 1 determines such an ejection failure in the ejector 3, the controller 1 performs cleaning of the ejector 3.
The ejector 3 includes a cleaning section 31 for cleaning an inkjet nozzle group. The cleaning section 31 has a suction cap 311, a suction tube 312, an electromagnetic on/off valve 313, a suction pump 314, a connection switching section 315, and a suction line 316.
Here, description will be given assuming that eight inkjet heads 30a to 30h are arranged in a row to form one inkjet nozzle group 30. Of course, the number of inkjet heads arranged in a row to form the inkjet nozzle group 30 of is limited to eight.
Moreover, for explanation purposes, the ejector 3 includes one cleaning section 31 for one inkjet nozzle group 30. In actual, the ejector 3 includes a plurality of cleaning sections 31 for a plurality of inkjet nozzle groups 30, respectively.
The suction cap 311 covers the inkjet nozzle group 30 so as to prevent the nozzles from being dried or contaminated. The suction cap 311 includes the suction tube 312 connected to the suction pump 314. The suction cap 311 performs covering as illustrated in
Here, suction caps 311a to 311h are provided for inkjet heads 30a to 30h, respectively.
The suction tube 312 is connected to the suction cap 311 as noted above. The suction pump 314 sucks ink via the suction tube 312 from the inkjet nozzle group 30 covered with the suction cap 311.
Here, suction tubes 312a to 312h are provided for the suction caps 311a to 311h, respectively, and are connected to the connection switching section 315 so as to allow suction.
In addition, a suction tube 312z is not connected to the suction cap 311 directly, but is connected to the switching section 315 so as to suck the interior of the connection switching section 315.
This achieves suction of ink from the suction caps 311a to 311h. Details thereof are to be mentioned later.
The electromagnetic on/off valve 313 is disposed on the suction line 316 via which the suction pump 314 and the connection switching section 315 are connected. As illustrated in
In addition, when the suction pump 314 collectively sucks ink from the inkjet heads 30a to 30h while the switching section 315 switchingly connects the suction tube 312z, the controller 1 controls the electromagnetic on/off valve 313 to open the suction line 316. Details thereof are to be mentioned later.
The suction pump 314 sucks the ink from the inkjet nozzle group 30 through the suction line 316, the connection switching section 315, the suction tube 312a to 312h or 312z, and the suction cap 311 under the state as in
When the suction pump 314 sucks the ink in the inkjet nozzle group 30, the controller 1 controls the connection switching section 315 to switch the suction line 316 and the suction tube 312a to 312h or 312z so as to individually suck the inkjet heads 30a to 30h forming the inkjet nozzle group 30 or collectively suck the inkjet heads 30a to 30h.
The connection switching section 315 is to be described in detail hereinafter with reference to
The housing 315h includes a sealed bearing 315j that enables to rotate the switching section 315k. The bearing 315j allows rotating the switching section 315k by a motor, not shown, while the interior of the housing 315h is kept sealed.
The plurality of suction ports 315i are disposed radially along the outer periphery of the housing 315h so as to correspond to the suction tubes 312a to 312h, and 312z.
Specifically, a suction port 315ia is connected to be in communication with the suction tube 312a. A suction port 315ib is connected to be in communication with the suction tube 312b. Hereinafter, similar connection is performed, and the suction port 315ih is similarly connected to be in communication with the suction tube 312h.
Moreover, the suction port 315iz is connected to be in communication with the suction tube 312z. Here, the suction tube 312z is connected to be in communication not with the inkjet nozzle group 30 but with an ink draw-off port 315o provided on the housing 315h.
The ink draw-off port 315o draws off the ink accumulated in the housing 315h when the inkjet nozzle group 30 is entirely sucked, which is to be mentioned later. The ink draw-off port 315o is preferably disposed on the bottom of the housing 315h for a suitable position of drawing off the accumulated ink, the position being in a negative (−) Y-axis direction when the direction is represented by X-, Y-, and Z-axes.
The housing 315h can be made from stainless steel, titanium, or fluorocarbon resin, the material having resistance to pressure upon suction by the suction pump 314 and resistance to corrosion from ink.
The switching section 315k has a substantially L-shape. The controller 1 controls the switching section 315k to rotate by the motor, not shown, whereby the switching section 315k is slidingly engaged in each of the plurality of suction ports 315i. When the switching section 315k is engaged in the suction port 315i, the suction tube 312 is brought into communication with the suction line 316. Consequently, the suction pump 314 enables to suck the ink from the inkjet nozzle group 30 covered with the suction cap 311.
The site where the switching section 315k is engaged in the suction port 315i preferably has a sealing construction, such as a grease seal, a rubber seal, or a metal seal, for obtaining efficient suction or entire suction of the inkjet nozzle group 30, to be mentioned later.
The plurality of suction ports 315ia to 315ih is connected to be in communication with the suction tubes 312a to 312h, respectively. The suction tube 312z connected to the suction port 315iz is connected to be in communication with the ink draw-off port 315o provided on the bottom of the housing 315h as illustrated. Such connection causes the switching section 315k to be slidingly engaged in the suction port 315iz, thereby bringing the suction tube 312z to be in communication with the suction line 316. Consequently, the suction pump 314 enables to suck the interior of the housing 315h.
The controller 1 controls the switching section 315k to rotate and be slidingly engaged in the suction port 315ia while the ejector 3 is in the state as illustrated in
When the ink is sucked from each of the inkjet heads 30b to 30h, the controller 1 controls the switching section 315k to rotate and be slidingly engaged in each of the suction ports 315ib to 315ih, thereby opening the electromagnetic on/off valve 313 and performing suction by the suction pump 314. Consequently, similar to the inkjet head 30a, the ink can be sucked from each of the inkjet heads 30b to 30h.
On the other hand, many number of inkjet heads forming the inkjet nozzle group 30 requires much time to repeatedly perform the operation as in
For instance, when ink is sucked in a manner as illustrated in
In order to solve the problem above, the housing 315h of the cleaning section 31 includes the ink draw-off port 315o for sucking the interior of the housing 315h.
The controller 1 controls the switching section 315k to rotate and be slidingly engaged in the suction port 315iz while the ejector 3 is in the state as illustrated in
Here, the housing 315h has a sealed construction. Consequently, negative pressure within the housing 315h is also applied to the suction caps 311a to 311h via the suction tubes 312a to 312h connected to the suction ports 315ia, respectively. This causes the ink to be discharged from the inkjet heads 30a to 30h.
The ink discharged from the inkjet heads 30a to 30h flows into the housing 315h via the suction caps 311a to 311h, the suction tubes 312a to 312h, and the suction ports 315ia to 315ih.
The ink flown into the housing 315h is discharged through the ink draw-off port 315o into the suction port 315iz. Here, the ink draw-off port 315o disposed on the bottom of the housing 315h collects the ink accumulated within the housing 315h naturally, resulting in efficient ink suction.
Thereafter, the ink is sucked by the suction pump 314 from the ink draw-off port 315o through the suction tube 312z and then through the switching section 315k slidingly engaged in the suction port 315iz. Accordingly, the ink is accumulated in the drain tank, not shown, of the inkjet printing apparatus 100.
As noted above, ink suction illustrated in
As noted above, the cleaning section 31 in
Moreover, ink accumulated in the suction caps 311a to 311 is sucked as in
Description has been given of the housing 315h of the connection switching section 315, the housing being substantially cylindrical and having a plurality of suction ports 315i along the outer periphery thereof. The location of the plurality of suction ports 315i in the housing 315h is not limited to this.
In a housing 3150h of the connection switching section 315 illustrated in
The switching section 3150k in
The site where the switching section 3150k is slidingly engaged in the suction port 3150i preferably has a sealing construction, such as a grease seal, a rubber seal, or a metal seal, for obtaining efficient suction or entire suction of the inkjet nozzle group 30.
In the connection switching section 315 in
Description has been given of the housing 315h or 3150h of the connection switching section 315 including ink draw-off port 315o or 3150o and suction port 315iz or 3150iz being connected to the suction tube 312z communicated with the ink draw-off port 315o or 3150o. Alternatively, the housing 315h or 3150h itself may include a suction path achieving the same function as the suction tube 312z.
In the inkjet printing apparatus 100, such a construction as above allows reduction in ink consumption due to the suction purge of the inkjet head having no need for suction purge can be achieved. Moreover, rapid cleaning can be performed selectively to the plurality of inkjet heads.
Modification
Description has been given of the housing 315h of the connection switching section 315 having a substantially cylindrical shape. Alternatively, the housing 315h may have a substantially cone, spherical zone, or spherical crown shape. Specifically, the housing 315h may have a shape with a plurality of suction ports 315i being arranged at an equal distance from the center of rotation of the switching section 315k. In this case, the similar effect as above can be produced.
In addition, description has been given of the connection switching section 315 disposed in the cleaning section 31 such that the switching section 315k has the center of rotation in a substantially horizontal direction. Alternatively, the connection switching section 315 may be disposed such that the switching section 315k has the center of rotation in a substantially vertical direction.
In this case, the ink draw-off port 315o on the bottom of the housing 315h causes the ink to be flown naturally and to be further accumulated. Consequently, the ink can be sucked efficiently from the entire inkjet nozzle group 30. Especially, the housing 315h having a substantially cone or spherical crown shape enables to increase efficiency.
Here, the solvent of ink to be cleaned by use in the inkjet printing apparatus 100 is not limited to water.
Moreover, the ink to be cleaned by use in the inkjet printing apparatus 100 may be not only dye ink used for general inkjet printing but also pigment ink.
Moreover, the ink to be cleaned by use in the inkjet printing apparatus 100 may be not only ink used for general printing but also functional ink used for circuit-pattern formation, biological tissue preparation, or three-dimensional shaping.
As noted above, this invention is suitable to an inkjet printing apparatus.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-065633 | Mar 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/005351 | 9/22/2011 | WO | 00 | 9/4/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/127543 | 9/27/2012 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20060268051 | Umeda et al. | Nov 2006 | A1 |
| 20070085874 | Shindo | Apr 2007 | A1 |
| 20090015625 | Sumida | Jan 2009 | A1 |
| 20110242203 | Yamamoto | Oct 2011 | A1 |
| Number | Date | Country |
|---|---|---|
| 2008-213216 | Sep 2008 | JP |
| 2010-125746 | Jun 2010 | JP |
| Entry |
|---|
| International Search Report for PCT Application No. PCT/JP2011/005351 dated Oct. 18, 2011, 1 page. |
| Number | Date | Country | |
|---|---|---|---|
| 20140002541 A1 | Jan 2014 | US |
