The above and other objects, features, advantages and technical and industrial significance of the present invention will be better understood by reading the following detailed description of preferred embodiments of the invention, when considered in connection with the accompanying drawings, in which:
Hereinafter, there will be described an inkjet recording apparatus according to one presently preferred embodiment of the invention, by referring to the accompanying drawings.
In
The sheet supply device 11 includes a sheet holder 11a as a medium holder, a pickup roller 11b, and an inversion guide plate 16b. The sheet holder 11a accommodates a stack of cut sheets P. More specifically, the sheet holder 11a has a supporting surface on which a stack of cut sheets P is placed. The pickup roller 11b is driven by a motor (not shown) to pick up the cut sheets P in the sheet holder 11a, one by one from the topmost one, and feed out each cut sheet P leftward as seen in
The feeding device 13 receives the cut sheet P from the sheet supply device 11, and feeds the cut sheet P. The feeding device 13 includes the feeder belt 8, a platen 15, and a nip roller 16a. The feeder belt 8 is an endless belt wound around two belt rollers 6, 7, and the platen 15 is disposed inside a circle formed by the endless feeder belt 8 and opposed to the four inkjet heads 1. The nip roller 16a is disposed at an uppermost stream position in the feeding device 13 with respect to the feed path. The nip roller 16a and the belt roller 6 nips therebetween the cut sheet P coming from the lower side, such that the cut sheet P is placed on the downward-facing surface of the feeder belt 8. The nip roller 16a is provided by an elastic member and presses the cut sheet P against the feeder belt 8, thereby enabling to the feeder belt 8 to feed the cut sheet P downstream. That is, at least an outer circumferential surface, i.e., a feeding surface, of the feeder belt 8 is formed of silicone resin to give such a tackiness that the cut sheet P pressure-sensitively adheres to the downward-facing surface of the feeder belt 8 when pressed by the nip roller 16a against the feeder belt 8.
The platen 15 functions to support the feeder belt 8 such that a gap between the feeder belt 8 and the inkjet heads 1 is held constant at a region where the platen 15 is opposed to the inkjet heads 1. This prevents a vertical disposition of the feeder belt 8.
With rotation of a feeder motor (not shown), the belt roller 6 rotates to circulate the feeder belt 8. The cut sheet P on the feeder belt 8 is fed by the circulation of the feeder belt 8. First, the cut sheet P is fed rightward as seen in
A separating plate 14 is disposed near a downstream end of the upward-facing surface 8b of the feeder belt 8. The cut sheet P fed by the feeder belt 8 is detached from the feeding surface of the feeder belt 8 by the separating plate 14 and ejected onto the catch tray 12, which is disposed downstream of the separating plate 14.
Inside each of the inkjet heads 1 are formed ink passages each having a nozzle 108 from which an ink droplet is ejected. As
A recording-area cover 3 is disposed to cover the inkjet heads 1 and a portion of the feeder belt 8 corresponding to the recording area A. A positive-pressure keeper 17 is attached to the recording-area cover 3, in order to keep positive an internal pressure of the recording-area cover 3. Thus, there is formed an air flow from an internal space of the recording-area cover 3 to an external space thereof, thereby preventing entrance of paper dust and ink mist into the recording-area cover 3.
More specifically, the recording-area cover 3 has a substantially box-like shape open downward. The positive-pressure keeper 17 is disposed on an upstream portion of an upper surface of the recording-area cover 3, and operates to hold positive the pressure in the internal space defined between the recording-area cover 3 and the upward-facing surface 8b of the feeder belt 8. In this internal space are formed an air flow from upstream to downstream with respect to the feeding direction, and an air flow over the upward-facing surface 8b and widthwise with respect to the feeder belt 8 (i.e., in the direction perpendicular to the feeding direction). As
As the cut sheet P is fed, foreign matter including that departing from the cut sheet P may be introduced into the recording area A. When such introduction of foreign matter to the recording area A occurs, the foreign matter tends to be deposited or land again on the cut sheet P or the ink ejection surfaces 2a more highly at an upstream portion of the recording area A. The provision of the air into the recording-area cover 3 from the upstream side by means of the positive-pressure keeper 17 effectively prevents the landing of foreign matter on the cut sheet P and the ink ejection surfaces 2a.
The remover roller 20 operates to remove the foreign matter such as paper dust from the recording surface of the cut sheet P being fed. The remover roller 20 is disposed near an upstream end of the downward-facing surface of the feeder belt 8 and opposed to the downward-facing surface. In the present embodiment, the remover roller 20 is positioned downstream of the nip roller 16a, and contacts the cut sheet P over the whole width of the cut sheet P. An area in the downward-facing surface which is opposed to the remover roller 20 constitutes a removing area B at which the foreign matter is removed from the recording surface of the cut sheet P.
An outer circumferential surface of the remover roller 20 has such a tackiness that when the outer circumferential surface of the remover roller 20 contacts the recording surface of the cut sheet P held on the downward-facing surface of the feeder belt 8, the foreign matter, such as paper dust, on the recording surface is moved away from the cut sheet P onto the remover roller 20. More specifically, the tackiness of the outer circumferential surface of the remover roller 20 is set at a sufficiently small value with respect to the tackiness of the feeding surface of the feeder belt 8 such that contact between the outer circumferential surface of the remover roller 20 and the cut sheet P does not cause detachment of the cut sheet P from the feeding surface of the feeder belt 8. However, this does not necessarily mean that the tackiness of the outer circumferential surface of the remover roller 20 per unit area is smaller than that of the feeding surface of the feeder belt 8. For instance, the tackiness per unit area may be equal therebetween. That is, an area at which the feeding surface of the feeder belt 8 contacts the cut sheet P is relatively wide whereas the outer circumferential surface of the remover roller 20 contacts the cut sheet P at a partial cylindrical surface which is relatively narrow, and equality in tackiness per unit area between the outer circumferential surface of the remover roller 20 and the feeding surface of the feeder belt 8 does not result in detachment of the cut sheet P from the feeding surface of the feeder belt 8. However, where the tackiness of the outer circumferential surface of the remover roller 20 per unit area is smaller than that of the feeding surface of the feeder belt 8, detachment of the cut sheet P from the feeding surface is inhibited with more reliability.
A removing-area cover 21 (shown in cross section in
In place of the remover roller 20, other kinds of removers may be employed. For instance, a rotatable brush may be employed. Where a rotatable brush is employed, it is significant to dispose the removing-area cover 21 in order to prevent that the foreign matter scattering around from the cut sheet P lands on the ink ejection surfaces of the inkjet heads 1 or back onto the cut sheet P. Alternatively, an antistatic brush may be employed in place of the remover roller 20. Where an antistatic brush is employed, static electricity as well as foreign matter is eliminated from the cut sheet P.
A dust tray 18 is disposed downstream of the remover roller 20 and opposed to the downward-facing surface of the feeder belt 8. The dust tray 18 receives the foreign matter scattering or falling from the recording surface of the cut sheet P. Foreign matter wafting inside the inkjet printer 101 often coalesces with ink mist and grows into particles so heavy as to naturally fall. The dust tray 18 receives such falling objects and thus contributes to preventing contamination inside the inkjet printer 101.
As described above, the cut sheet P is fed out from the sheet holder 11a of the sheet supply device 11 leftward as seen in
According to the embodiment described above, the foreign matter on the recording surface of the cut sheet P is removed by the remover roller 20 while the cut sheet P pressure-sensitively adheres to the downward-facing surface of the feeder belt 8 with the recording surface thereof facing downward. A portion of the foreign matter may scatter upon the removal, but the foreign matter thus scattering falls downward below the feeder belt 8. Hence, the scattering foreign matter is reliably inhibited from landing on the ink ejection surfaces 2a of the inkjet heads 1 which are located above the upward-facing surface 8b of the feeder belt 8.
Since the inkjet heads 1 and a portion of the feeder belt 8 corresponding to the recording area A are covered by the recording-area cover 3, the scattering foreign matter is further reliably inhibited from landing on the ink ejection surfaces 2a.
Since the positive-pressure keeper 17 holds positive the internal pressure of the recording-area cover 3, an air flow is generated from the internal space of the recording-area cover 3 to the external space thereof, thereby preventing entrance of the scattering foreign matter into the recording-area cover 3. Thus, landing of the foreign matter on the ink ejection surfaces 2a is further reliably inhibited.
Since the remover roller 20 and a portion of the feeder belt 8 corresponding to the removing area B are covered by the removing-area cover 21, the foreign matter departing from the recording surface of the cut sheet P is prevented from scattering around.
Although there has been described one embodiment of the invention, it is to be understood that the invention is not limited to the details of the embodiment but may be otherwise embodied with various modifications and improvements that may occur to those skilled in the art, without departing from the scope and spirit of the invention defined in the appended claims.
For instance, in the above-described embodiment the recording-area cover 3 covers only the inkjet heads 1 and a part of the feeder belt 8 which includes the portion corresponding to the recording area A. However, the recording-area cover 3 may further cover the upward-facing surface 8b of the feeder belt 8 and another area over the upward-facing surface 8b. Alternatively, the recording-area cover 3 may be omitted.
Although in the above-described embodiment the inkjet printer 101 includes the positive-pressure keeper 17 that keeps positive the internal pressure of the recording-area cover 3. However, such a positive-pressure keeper 17 may be omitted.
In the above-described embodiment, the removing-area cover 21 covers only the remover roller 20 and a part of the feeder belt 8 which includes the portion corresponding to the removing area B. However, the removing-area cover 21 may further cover another area of the feeder belt 8 except the upward-facing surface 8b. Alternatively, the removing-area cover 21 may be omitted.
The remover roller 20 in the above-described embodiment removes the foreign matter on the cut sheet P by way of its contact with the cut sheet P over the whole width of the cut sheet P. However, the embodiment may be modified such that the remover roller 20 contacts only opposite widthwise ends of the cut sheet P. This also applies where a remover other than a roller is employed. That is, since paper dust tends to occur at opposite widthwise ends of a cut sheet of paper, cleansing merely the opposite widthwise ends is effective to sufficiently inhibit landing of paper dust on the ink ejection surfaces 2a.
The cut sheet P as a recording medium can be easily held on the outer circumferential surface or the feeding surface of the feeder belt 8 where the feeding surface has a tackiness, as in the above-described embodiment. However, the way of holding the cut sheet P on the feeding surface is not limited to that described above. For instance, it may be arranged such that the feeder belt 8 is formed of a material having an air permeability, and the air is sucked through the feeder belt 8 from an inner circumferential side of the feeder belt 8 in order to hold the cut sheet P on the feeding surface of the feeder belt 8.
Although the inkjet printer 101 of the embodiment is a line printer, the invention is applicable to other types of inkjet printers, such as serial printer.
It is noted that although in the above-described embodiment the positive-pressure keeper 17 is disposed on the upper surface of the recording-area cover 3, the positive-pressure keeper 17 may be disposed at other positions in the printer. Where the positive-pressure keeper 17 is disposed at other positions in the printer, it may be arranged such that an air positively pressurized is supplied to the internal space of the recording-area cover 3 through a tube.
Number | Date | Country | Kind |
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2006208692 | Jul 2006 | JP | national |