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 presently preferred embodiments of the invention with reference to the accompanying drawings.
Referring to
In
The sheet supply device 11 includes a sheet holder 11a as a medium holder, a pickup roller 11b, guide rollers 16a, 16a′, and a pair of guide plates 16b, namely, an inner guide plate and an outer guide plate. The guide plates 16b function as a first turnover guide. The sheet holder 11a accommodates a stack of cut sheets P. The pickup roller 11b is driven by a motor (not shown) to sequentially pick up the cut sheets P from inside the sheet holder 11a from the topmost sheet P, and feed out the cut sheet P leftward as seen in
The feeding device 13 feeds the cut sheet P as fed out from the sheet supply device 11, and includes the intermediate feeder belt 17a, a guide plate 18 as a second turnover guide, a primary feeder belt 8, a platen 15, and a nip roller 17b′. The intermediate feeder belt 17a is an endless belt wound around two belt rollers 17b, 17c, and the primary feeder belt 8 is an endless belt wound around two belt rollers 6, 7. The platen 15 is disposed inside a circle formed by the endless feeder belt 8 and opposed to the four inkjet heads 1. At least the feeding surface of the intermediate feeder belt 17a is formed of silicone resin, and thus the feeding surface of the intermediate feeder belt 17 has such a tackiness that the cut sheet P fed out from the sheet supply device 11 is nipped between the nip roller 17b′ and the belt roller 17b disposed adjacent to the nip roller 17b′ in pressed contact to pressure-sensitively adhere to the feeding surface of the intermediate feeder belt 17a. The cut sheet P is fed upward and rightward as seen in
The cut sheet P as detached from the feeding surface of the intermediate feeder belt 17a by the separating plate 17d is guided by the guide plate 18 onto an outer circumferential surface, or a feeding surface, of the primary feeder belt 8 disposed above the intermediate feeder belt 17a. The feeding surface of the primary feeder belt 8 also has a tackiness. The guide plate 18 is curved along an outer circumferential surface of the belt roller 7. More specifically, the guide plate 18 functions to upward feed the cut sheet P as detached from the feeding surface of the intermediate feeder belt 17a, while turning over the cut sheet P, and change the feeding direction from rightward to leftward as seen in
When a feeder motor (not shown) rotates the belt roller 6, the primary feeder belt 8 circulates and feeds the cut sheet P that is pressed onto the feeding surface thereof by the nip roller 4 and pressure-sensitively adhering thereto. The cut sheet P is thus fed toward the catch tray 12 via an area where the cut sheet P is opposed to the inkjet heads 1.
At a position on the primary feeder belt 8 and near a sheet ejection opening, there is disposed a separating plate 14. The cut sheet P having been fed by the primary feeder belt 8 is detached from the feeding surface of the primary feeder belt 8 by the separating plate 14, and ejected onto the catch tray 12 disposed downstream of the primary feeder belt 8.
The four inkjet heads 1 are for ejecting droplets of respective color inks, i.e., magenta, yellow, cyan, and black inks, and arranged along a feeding direction in which the cut sheet P is fed. That is, the inkjet printer 101 is a line printer. In each of the inkjet heads 1 are formed ink passages each including a nozzle 108 from which an ink droplet is ejected. Each inkjet head 1 is a rectangular parallel-piped long in a direction perpendicular to the feeding direction. An under surface of the inkjet head 1 constitutes an ink ejection surface 2a in which the nozzles 108 open. A part of the opposingly-feeding surface of the primary feeder belt 8, is opposed to the ink ejection surfaces 2a of the inkjet heads 1, extends along the feed path of the cut sheet P, and corresponds to a recording area A. As the cut sheet P is fed by the primary feeder belt 8 and passes through the recording area A, i.e., just under the four inkjet heads 1, droplets of the respective color inks are ejected from the ink ejection surfaces 2a of the inkjet heads 1 toward the recording surface of the cut sheet P, in order to form or record a desired color image within a printing area in the cut sheet P. A recording-area cover 3 is disposed to cover the inkjet heads 1 and a portion of the primary feeder belt 8 corresponding to the recording area A. A positive-pressure keeper 17 is attached to the recording-area cover 3. The positive-pressure keeper 17 keeps 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.
The remover roller 20 operates to remove the foreign matter, e.g., paper dust, from the recording surface of the cut sheet P being fed by the intermediate feeder belt 17a. The remover roller 20 is disposed near an upstream end of the intermediate feeder belt 17a at which the cut sheet P is received by the intermediate feeder belt 17a. The remover roller 20 contacts a downward-facing surface in the feeding surface of the intermediate feeder belt 17a. A planar surface in the downward-facing surface of the feeding surface of the intermediate feeder belt 17a, which planar surface is opposed to the remover roller 20, corresponds to a removing area B where 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 on the downward-facing surface of the feeding surface of the intermediate feeder belt 17a, 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 intermediate feeder belt 17a, such that contact between the remover roller 20 and the cut sheet P does not cause detachment of the cut sheet P from the intermediate feeder belt 17a. 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 intermediate feeder belt 17a. For instance, the tackiness per unit area may be equal between the outer circumferential surface of the remover roller 20 and the feeding surface of the intermediate feeder belt 17a. That is, an area at which the intermediate feeder belt 17a contacts the cut sheet P is relatively wide whereas 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 intermediate feeder belt 17a does not result in detachment of the cut sheet P from the feeding surface of the intermediate feeder belt 17a. 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 intermediate feeder belt 17a, detachment of the cut sheet P from the intermediate feeder belt 17a is inhibited with more reliability.
In place of the remover roller 20, other kinds of removers may be employed. For instance, an antistatic brush or an antistatic blower for eliminating static electricity may be employed in place of the remover roller 20.
The removing area B is located under an “opposingly-feeding surface” in the feeding surface of the primary feeder belt 8. The opposingly-feeding surface includes or encompasses the recording area A, and extends along the feed path of the cut sheet P. The opposingly-feeding surface is a planar surface having a greatest area among all the planar surfaces included in the feeding surfaces of the primary feeder belt 8 and the intermediate feeder belt 17a. As
As described above, the cut sheet P is fed out by the pickup roller 11b, leftward as seen in
As illustrated above, in the present embodiment the removing area B is disposed under the primary feeder belt 8 and within the area corresponding to the primary feeder belt 8 as seen in the vertical direction. Hence, the foreign matter, which has scattered from the recording surface of the cut sheet P upon the removal of the foreign matter from the recording surface and wafts, is inhibited from entering a clearance between the primary feeder belt 8 and the ink ejection surfaces 2a. Therefore, the wafting foreign matter is reliably inhibited from landing on the ink ejection surfaces 2a.
Since the whole remover roller 20 is disposed within the area corresponding to the primary feeder belt 8 as seen in the vertical direction, the inkjet printer 101 can be downsized.
The recording surface of the cut sheet P does not once face vertically upward at the segment between the removing area B and the primary feeder belt 8, that is, after the cut sheet P has passed the removing area B and before the cut sheet P is placed on the primary feeder belt 8. Thus, the foreign matter, e.g., paper dust, that has been once removed does not tend to land back on the cut sheet P. Hence, landing of foreign matter on the ink ejection surfaces 2a via the cut sheet P is reliably inhibited.
Since the inkjet heads 1 and the portion of the primary feeder belt 8 corresponding to the recording area A are covered by the recoding-area cover 3, landing of foreign matter on the ink ejection surfaces 2a is further reliably inhibited.
Since the remover roller 20 and the part of the intermediate feeder belt 17a 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 in the above-described embodiment, the feed path in the inkjet printer 101 along which the cut sheet P is fed is S-shaped in side view, the feed path may have other shapes. For instance, the feed path may be U-shaped. Hereinafter, there will be described an inkjet printer 201 according to a second embodiment of the invention, in which the feed path is U-shaped, by referring to
In the second embodiment, the intermediate feeder belt 17a used in the first embodiment is omitted, and a cut sheet P as turned over or turned 180-degree by a turnover guide plate 216b is made to pressure-sensitively adhere to a downward-facing surface 208a of a feeder belt 208.
In the first embodiment, the cut sheet P is guided and turned over by a pair of guide plates 16b, namely, an outer guide plate and an inner guide plate. In the second embodiment, on the other hand, the inner guide plate 16b is omitted and a guide roller 216a having a relatively large diameter is employed, and the cut sheet P is guided by an outer circumferential surface of the guide roller 216a and the guide plate 216b.
Further, a dust tray 218 is disposed between the downward-facing surface 208a of the feeder belt 208 and the sheet holder 11a. More specifically, the dust tray 218 is disposed above a topmost one of a stack of cut sheets P accommodated in the sheet holder 11a, with a clearance between the dust tray 218 and the topmost cut sheet P. The dust tray 218 has such a size as to cover almost an entire upper surface of the topmost cut sheet P. Hence, dust wafting inside the inkjet printer 201 is effectively prevented from accumulating on the upper surface of the topmost cut sheet P.
The other parts of the second embodiment are identical with the first embodiment and description thereof is omitted.
Although two presently preferred embodiments of the invention have been described above, the invention is not limited to details thereof, but may be otherwise embodied with various modifications which do not depart from the scope and spirit of the invention as defined in the appended claims.
For instance, although in each of the above-described embodiments the whole remover (namely, remover roller 20) is disposed within the area corresponding to the primary feeder belt 8, or the feeder belt 208, as seen in the vertical direction. However, at least a part of the remover may be outside the area corresponding to the primary feeder belt 8 or the feeder belt 208 as seen in the vertical direction.
In the first embodiment, the feed path along which the cut sheet P is fed is constructed such that the recording surface of the cut sheet P does not once face vertically upward at the segment of the feed path between the removing area B and the primary feeder belt 8. Similarly, in the second embodiment, the feed path is constructed such that the recording surface does not once face vertically upward at a segment of the feed path between the removing area B and the opposingly-feeding surface 8b of the feeder belt 208. However, the feed paths may be constructed such that the recording surface of the cut sheet P faces vertically upward somewhere in these segments.
In each of the above-described embodiments, the recording-area cover 3 covers only the inkjet heads 1 and a part of the primary feeder belt 8, or the feeder belt 208, which part includes the portion corresponding to the recording area A. However, the recording-area cover 3 may further cover a surface of the primary feeder belt 8 or the feeder belt 208 which surface includes the recording area A, and also another area over the surface. Alternatively, the recording-area cover 3 may be omitted.
In each of the above-described embodiments, the removing-area cover 21 covers only the remover roller 20 and a part of the intermediate feeder belt 17a, or the feeder belt 208, which part includes the portion corresponding to the removing area B. However, in the first embodiment, the removing-area cover 21 may further cover another area of the feeding surfaces except the opposingly-feeding surface in the primary feeder belt 8 which surface includes the recording area A. For instance, the removing-area cover 21 may cover substantially the whole intermediate feeder belt 17a. Similarly, in the second embodiment, the removing-area cover 21 may further cover another area of the feeder belt 208 except the opposingly-feeding surface including the recording area A. Alternatively, the removing-area cover 21 may be omitted in each of the above-described embodiments.
In each of the above-described embodiments, the endless belt 17a, 8, 208 constructs a part of the feed path of the cut sheet P. However, in place of the endless belt, rollers or guide plates may be employed to construct the feed path.
As in the above-described embodiments, the cut sheet P as a recording medium can be easily held on the outer circumferential surface or feeding surface of each feeder belt 17a, 8, 208, when the feeding surface has a tackiness. However, the way in which the cut sheet P is held on the feeding surface is not limited thereto. For instance, it may be arranged such that the feeder belt 17a, 8, 208 is formed of a material having an air permeability, and the air is sucked through the feeder belt 17a, 8, 208 from the inner circumferential side of the belt 17a, 8, 208 in order to hold the cut sheet P on the feeding surface.
Although each of the above-described inkjet printers 101, 201 is a line printer, the invention is applicable to other types of inkjet printers, such as serial printer.
Number | Date | Country | Kind |
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2006207833 | Jul 2006 | JP | national |
2006208692 | Jul 2006 | JP | national |