Patent Grant
11479043
The disclosure of Japanese Patent Application No. 2020-051336 filed on Mar. 23, 2020 including specification, drawings and claims is incorporated herein by reference in its entirety.
This invention relates to a printing apparatus for printing by discharging an ink to the upper surface of a base material.
A printing apparatus is known which prints an image on the upper surface of a base material by ejecting an ink such an aqueous or oil-based ink from a head part to the base material by an ink-jet method. For example, in a printing apparatus described in JP 2019-119609A, a plurality of head parts each having a nozzle surface on a lower surface are arrayed along a printing path for a base material. Each head part prints by ejecting an ink in the form of droplets to the upper surface of the base material from the nozzle surface. Thus, if deposits attached to the nozzle surfaces are dried and solidified, the clogging of nozzles occurs to reduce printing performance. Accordingly, although not described in JP 2019-119609A, various maintenance operations are performed with the entire nozzle surfaces covered from below by box-shaped cover members open to face the lower surfaces of the head parts in this printing apparatus. One of the maintenance operations is an ink purging process. One of main purposes of this purging process is to prevent deposits attached to the nozzle surfaces of the head parts from being dried and solidified and push out the ink at every certain time.
In some of the head parts equipped in the printing apparatus described in JP 2019-119609A, printing is performed in such a posture that a normal to the nozzle surface is inclined with respect to a vertical direction (hereinafter, referred to as an “inclined posture”). Further, the purging process is also performed in the inclined posture. Thus, the ink may drip along the inclined nozzle surface before dropping from the nozzle surface during the purging process. The thus dripped ink is attached to an upper part of a side wall of the cover member open to face the lower surface of the head part and causes various troubles. For example, if the ink deposits and is solidified and part thereof is transferred to the nozzle surface, it leads to a reduction in printing quality.
This invention was developed in view of the above problem and aims to effectively prevent the reattachment of an ink to a nozzle surface in a printing apparatus for printing by ejecting the ink to the upper surface of a base material from the nozzle surface provided in a head part in an inclined posture.
One aspect of the invention is a printing apparatus for printing by discharging an ink to an upper surface of a base material in the form of an elongated strip. The apparatus comprises: a head part provided with a nozzle surface for ejecting the ink in a central part of a lower surface having a rectangular shape; and a cover member having a box shape open upward by having a plurality of side walls rising upward from a periphery of an inner bottom surface, the cover member covering the nozzle surface from below by being arranged below the head part, wherein: the lower surface has a first short side and a second short side parallel to a longitudinal direction of the base material and a first long side and a second long side parallel to a width direction of the base material, the head part is arranged in such an inclined posture that the first long side is located below the second long side in a vertical direction and a first lower surface peripheral edge portion extending along the first long side, out of a peripheral edge part of the lower surface, is located vertically lowest, and the plurality of side walls include a first side wall having an upper end portion located away from the first long side toward a side opposite to the second long side in the longitudinal direction.
According to this invention, since the head part is arranged in the inclined posture, the ink ejected from the nozzle surface may drip to the first lower surface peripheral edge portion along the nozzle surface, for example, if a purging process or the like is performed. Accordingly, the first side wall, which is one of the side walls constituting the cover member, is so provided that the upper end portion is located away from the first long side toward the side opposite to the second long side in the longitudinal direction. Thus, the ink dripped to the first lower surface peripheral edge portion drops from the first long side by the self-weight thereof after reaching the first long side of the lower surface of the head part, and is collected by the cover member without being attached to the upper end portion of the first side wall. Therefore, the ink can be prevented from being solidified at the first lower surface peripheral edge portion and the reattachment of the ink to the nozzle surface can be effectively prevented.
All of a plurality of constituent elements of each aspect of the invention described above are not essential and some of the plurality of constituent elements can be appropriately changed, deleted, replaced by other new constituent elements or have limited contents partially deleted in order to solve some or all of the aforementioned problems or to achieve some or all of effects described in this specification. Further, some or all of technical features included in one aspect of the invention described above can be combined with some or all of technical features included in another aspect of the invention described above to obtain one independent form of the invention in order to solve some or all of the aforementioned problems or to achieve some or all of the effects described in this specification.
In the printing apparatus 100, as shown in
The front-stage printer 110 includes a conveyor 10 for conveying the base material BM from right to left as shown in a partial enlarged view in
Out of the plurality of backup rollers 13, the most upstream backup roller 13 and the most downstream backup roller 13 in a conveying direction are at the same height position, and front-stage printing is performed between these rollers. That is, a path between these two backup rollers 13, 13 is set as a front-stage printing path. The plurality of backup rollers 13 are arranged at certain intervals along the front-stage printing path. These plurality of backup rollers 13 are arranged at a higher position toward a central part of the front-stage printing path and support the base material BM. As a result, the conveying direction of the base material BM is not constant. The conveying direction of the base material BM is obliquely upward with respect to the horizontal direction X in a first half of the front-stage printing path, substantially parallel to the horizontal direction X in the central part and obliquely downward with respect to the horizontal direction X in a second half. That is, the conveyor 10 can continuously convey the base material BM in the form of an elongated strip by an upward projecting substantially arcuate front-stage printing path.
A plurality of head parts 2 for printing by ejecting the ink to the upper surface of the base material BM being conveyed in this way are arranged along the front-stage printing path. More specifically, the head part 2 is arranged at a position above the upper surface of the base material BM moving between two backup rollers 13 adjacent to each other. Each head part 2 ejects the ink to the printed surface of the base material BM having both sides supported by two backup rollers 13 in an ink-jet method. In an example shown here, six head parts 2 including four head parts 2 for ejecting ink of four process colors (yellow, magenta, cyan, black) and two head parts 2 for ejecting ink of two specific colors (orange, violet, green, etc.) are provided. Each head part 2 has a nozzle surface for ejecting the ink on a lower surface, and ejects the ink from this nozzle surface to the upper surface of the base material BM being conveyed along the substantially arcuate conveyance path. Therefore, as will be described in detail later, the head part 2 is arranged in an inclined posture according to the conveying direction of the front-stage printing path.
Here, the “maintenance position” means a position where maintenance is performed for the head part 2. Each head part 2 ejects the ink from the nozzle surface in a so-called ink-jet method. Thus, if a printing process is performed for a long time, a nozzle eject failure gradually occurs. Further, when printing is temporarily stopped, the ink attached to the nozzle surface may be solidified to cause a eject failure. Accordingly, before printing is resumed, the head part 2 is positioned at the maintenance position slightly higher than the printing position. Further, a maintenance part 3 performs various types of maintenance for the nozzle surface of the head part 2.
The maintenance part 3 has a function of performing a purging process and a wiping process for the head part 2 having a nozzle with a eject failure, and is provided for each head part 2. The maintenance part 3 is connected to a maintenance driver 39. Thus, the maintenance driver 39 operates in response to a horizontal movement command from the controller, thereby moving in the width direction Y of the base material BM. More particularly, the maintenance part 3 reciprocally moves between a standby position (solid-line position of
Here, the “printing state” means a state where the head part 2 is positioned at the print position so that a nozzle surface 21 is right above and proximate to the base material BM as shown in a partial enlarged view in
The head part 2 includes a head base 22 inclined with respect to the vertical direction Z. The head base 22 extends in parallel to the width direction Y of the base material BM. Recording heads 23 having nozzles on lower surfaces are fixed to a side surface of this head base 22 while being arrayed in the Y direction. In this way, a lower surface 24 of the head part 2 has a rectangular shape when viewed from the base material BM. More particularly, the lower surface 24 has short sides 241, 242 parallel to a longitudinal direction of the base material BM and long sides 243, 244 parallel to the width direction Y of the base material BM.
A central part of the lower surface 24 having such a rectangular shape serves as the nozzle surface 21 for ejecting the ink. Further, a region excluding the nozzle surface 21, out of the lower surface of the head part 2, i.e. a region surrounding the nozzle surface 21, serves as a peripheral edge part 25 which does not eject the ink. Further, since the head part 2 is arranged in the inclined posture to correspond to the front-stage printing path for the base material BM, the long side 243 is located below the long side 244 in the vertical direction Z as shown in
In the head part 2, to protect the plurality of recording heads 23, a guard member 26 is mounted on a side opposite to the head base 22 across the plurality of recording heads 23 as shown in
The maintenance part 3 includes the box-shaped cover member 30 open upward. As shown in
Further, as shown in
If the cover member 30 having such a configuration is arranged at the maintenance position by the maintenance driver 39, each part of the cover member 30 is positioned as below to cover the nozzle surface 21 of the head part 2 from below. Specifically, as shown in a dotted line of
If the head part 2 is moved downward to the maintenance position where the purging process is performed by the head driver 29 after the cover member 30 is arranged at the maintenance position below the head part 2 located at the retracted position, the lower surface 24 of the head part 2 comes closer to the cover member 30. More particularly, as shown in a field (b) of
In this embodiment, the airtight controller 4 for enhancing the airtightness of an atmosphere surrounding the nozzle surface 21 is provided not only to merely collect the ink by the cover member 30, but also to satisfactorily perform maintenance such as the purging process. Here, the airtight controller 4 seals the nozzle surface 21 from outside using contact members 41 to 44, which are elastic bodies, and rubber sponges are used as an example of the elastic bodies. The contact members 41 to 44 respectively correspond to the four side walls 31 to 34 of the cover member 30, and the contact members 41, 42 and 44 are mounted on the cover member 30, whereas the contact member 43 is mounted on the head part 2. Note that, in
As shown in a partial enlarged view of
In performing printing in the printing apparatus 100 thus configured, the head part 2 and the maintenance part 3 are in the printing state. That is, the head part 2 is positioned above the front-stage printing path for the base material BM and the maintenance part 3 waits at a position separated in the width direction Y from the front-stage printing path. Thus, as shown in
In performing the purging process as part of maintenance, if the head part 2 and the cover member 30 approach each other as shown in
Further, the head part 2 is in the inclined posture and the nozzle surface 21 is inclined toward the left-lower side as shown in the field (b) of
As just described, in this embodiment, the short sides 241, 242 respectively correspond to examples of a “first short side” and a “second short side” of the invention, and the long sides 243, 244 respectively correspond to examples of a “first long side” and a “second long side” of the invention. Further, out of the side walls 31 to 34 of the cover member 30, the side wall 33 corresponds to an example of a “first side wall” of the invention, whereas the remaining side walls 31, 32 and 34 correspond to an example of a “second side wall” of the invention. Further, the contact member 43 corresponds to an example of a “side surface contact member” of the invention, whereas the contact members 41, 42 and 44 correspond to an example of a “lower surface contact member” of the invention.
In the second embodiment, two contact members 431, 432 are mounted on a guard member 26 of a head part 2, instead of the contact member 43 of the first embodiment. As shown in
In performing printing in a printing apparatus 100 thus configured, the head part 2 is positioned above a front-stage printing path for a base material BM as shown in a field (a) of
In performing a purging process as part of maintenance, if the head part 2 and a cover member 30 approach each other as shown in a field (b) of
Further, also in the second embodiment, the upper end portion 331 of a side wall 33 on the side of the first lower surface peripheral edge portion 251 is separated from a lower surface 24 of the head part 2 and sealing on the side of the first lower surface peripheral edge portion 251 is performed with the contact members 431, 432 separated from the first lower surface peripheral edge portion 251 as in the first embodiment. Thus, an ink dripping from the nozzle surface 21 is reliably collected into a collection space SP via the first lower surface peripheral edge portion 251 as shown by a broken-line arrow of
In the third embodiment, a contact member 433 functioning as a “second head contact member” of the invention is provided instead of the contact member 432 functioning as the “cover contact member” of the invention. This contact member 433 is mounted on the side wall 33 by a support member 45 in such a posture as to project further upward than an upper end portion 331 of the side wall 33 as shown in a field (b) of
In performing printing in a printing apparatus 100 thus configured, the head part 2 is positioned above a front-stage printing path for a base material BM as shown in a field (a) of
In performing a purging process as part of maintenance, if the head part 2 and the cover member 30 approach each other as shown in a field (b) of
Further, also in the third embodiment, the upper end portion 331 of the side wall 33 on the side of a first lower surface peripheral edge portion 251 is separated from the lower surface 24 of the head part 2 and sealing on the side of the first lower surface peripheral edge portion 251 is performed with the contact members 431, 433 separated from the first lower surface peripheral edge portion 251 as in the second embodiment. Thus, an ink dripping from the nozzle surface 21 is reliably collected into a collection space SP via the first lower surface peripheral edge portion 251 as shown by a broken-line arrow of
Note that the invention is not limited to the embodiments described above and various changes other than the aforementioned ones can be made without departing from the gist of the invention. For example, although the elastic bodies constituting the contact members 41 to 44, 431 to 433 are constituted by rubber sponges in the above embodiments, other elastic bodies capable of being elastically deformed to close the clearance between the head part 2 and the cover member 30 may be used instead of the rubber sponges. Further, although the contact members 41 to 44, 431 to 433 are entirely constituted by the elastic bodies, only parts to be held in contact with the head part 2 and the cover member 30 may be constituted by elastic bodies. It is further desirable that parts of the contact members in contact with each other are also constituted by elastic bodies.
Further, in the above embodiments, the invention is applied to a case where the head part 2 is in such an inclined posture that the long side 243 located on a downstream side in the conveying direction of the base material BM is lower in the vertical direction Z than the long side 244 on an upstream side (two head parts 2 located on a downstream side in the front-stage printer 110). However, the invention can be also applied to a case where the head part 2 is in an inclined posture inclined toward an opposite side (three head parts 2 located on an upstream side in the front-stage printer 110 and a head part in the rear-stage printer 130).
Further, although the head driver 29 and the maintenance driver 39 constitute the “mover” of the invention and a switch is made between the printing state and the maintenance state by these in the above embodiments, a switch may be made between the printing state and the maintenance state by moving only the head part 2 by the head driver 29 while fixedly arranging the maintenance part 3.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as other embodiments of the present invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.
This invention is generally applicable to a printing apparatus for printing by ejecting ink from a nozzle surface provided in a head part in an inclined posture.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2020-051336 | Mar 2020 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6709087 | Ansell et al. | Mar 2004 | B2 |
| 20160200106 | Nakano | Jul 2016 | A1 |
| 20160207315 | Tsuzawa | Jul 2016 | A1 |
| 20170266964 | Hattori | Sep 2017 | A1 |
| Number | Date | Country |
|---|---|---|
| 1 375 157 | Jan 2004 | EP |
| 2014-008639 | Jan 2014 | JP |
| 2019-119609 | Jul 2019 | JP |
| WO-2015046196 | Apr 2015 | WO |
| 2019131843 | Jul 2019 | WO |
| Entry |
|---|
| Extended European Search Report issued in corresponding European Patent Application No. 21158230.9-1017, dated Aug. 5, 2021. |
| Number | Date | Country | |
|---|---|---|---|
| 20210291529 A1 | Sep 2021 | US |
