1. Field of the Invention
The present invention relates to an inkjet type recording apparatus using a line type recording head.
2. Description of the Related Art
In an inkjet type recording apparatus, it can happen that the ink within the head nozzles is dried and increases its viscosity to be solidified. Further, in some cases, paper powder, dust, bubbles, etc. may get mixed with the ink in the nozzles, which leads to defective ink ejection due to clogging, resulting in deterioration in recording quality. Thus, it is necessary to perform cleaning on the recording head.
US 2008/0007592 discusses a cleaning mechanism which performs wiping with a wiper blade inclined non-parallel to the direction in which the nozzle array is formed. By inclining the wiper blade, the ink scraped off from the nozzle surface is gathered at one end portion and the gathered ink is wiped off by another wiper.
As shown in
If wiping is performed on the recording head of this construction, which has the sealing portions 23 swollen higher than the nozzle surface 22, by using the wiper blade as discussed in US 2008/007592, the following problem occurs.
Since the wiper blade is obliquely inclined, an end portion of the wiper blade first passes the nozzle surface 22 to reach the sealing portion 23. Depending upon the inclination angle of the wiper blade, the forward portion thereof may climb onto the sealing portion 23 while the remaining portion thereof is wiping the nozzle arrays. Then, the wiper blade as a whole is raised, and the intimate contact between the portion opposing the nozzle arrays and the nozzle arrays becomes rather insufficient, making it impossible to perform proper wiping on the nozzles.
The present invention is directed to realization of a cleaning function that makes it possible to reliably perform wiping on a nozzle surface of a recording apparatus in which a plurality of nozzle arrays are formed.
According to an aspect of the present invention, a apparatus includes a recording head having a nozzle surface having a plurality of nozzle arrays arranged in parallel, and a sealing portion arranged in proximity to the plurality of nozzle arrays and protruding beyond the nozzle surface, and a wiper unit capable of relatively moving with respect to the nozzle surface in a wiping direction parallel to the nozzle surface and configured to wipe the nozzle surface, wherein the wiper unit has a first wiper blade and a second wiper blade, the first wiper blade is arranged to be inclined by an angle θ1 (θ1>0) with respect to a direction orthogonal to the wiping direction within a plane parallel to the nozzle surface, and wherein the second wiper blade is arranged to be inclined by an angle θ2 (θ2<0) with respect to the direction orthogonal to the wiping direction within the plane.
According to the present invention, a recording apparatus equipped with a wiper unit capable of more reliably wiping a nozzle surface having a plurality of nozzle arrays is realized.
Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
Specific exemplary embodiments of the present invention will be described with reference to the drawings.
A recording apparatus 1 according to the present exemplary embodiment is a line printer adapted to perform printing equipped with an elongated line head and adapted to perform printing while continuously conveying a sheet in a conveyance direction (first direction). It is equipped with a holder retaining a sheet 4 in the form of a roll, a conveyance mechanism 7 conveying the sheet 4 in the first direction at a predetermined speed, and a recording unit 3 performing recording on the sheet 4 by line heads. The sheet used in the embodiment is not restricted to a continuous roll sheet; it is also possible to adopt cut sheets. The recording apparatus 3 is further equipped with a cleaning unit 6 adapted to perform cleaning on a nozzle surface of a recording head through wiping. Further, there are provided, along the sheet conveyance path, a cutter unit situated on the downstream side of the recording unit 3 and adapted to cut the sheet 4, a drying unit forcibly drying the sheet, and a discharge tray.
The recording unit 3 is equipped with a plurality of recording heads 2 respectively corresponding to inks of different colors. Although this exemplary embodiment uses four recording heads corresponding to the four colors of cyan (C), magenta (M), yellow (Y), and black (K), the number of colors is not restricted to four. The inks of the different colors are respectively supplied to the recording heads 2 via ink tubes. The plurality of recording heads 2 are integrally held by a head holder 5; there is provided a mechanism allowing vertical movement of the head holder 5 so that the distance between the plurality of recording heads 2 and the surface of the sheet 4 can be varied.
The cleaning unit 6 has a plurality of (four) cleaning mechanisms 9 in correspondence with the plurality of (four) recording heads 2. The cleaning unit 6 as a whole can slide in a first direction.
The ink absorbing members 16a and 16b are rollers formed of a porous material of high absorptivity and adapted to be driven to rotate. The ink absorbing members 16 are provided so as to be in contact with the nozzle surface 22 at two positions corresponding to both ends of the wiper blade 11. After the wiping by the wiper blade 11, ink and dust overflowing from both ends of the wiper blade 11 and remaining on the nozzle surface 22 are absorbed and recovered by the ink absorbing members 16a and 16b.
The first wiper blade 12a is arranged so as to be inclined with respect to the first direction by an angle θ1. The first wiper blade 12b is arranged so as to be inclined with respect to the first direction by an angle −θ1. The second wiper blade 13a is arranged so as to be inclined with respect to the first direction by an angle θ2. The second wiper blade 12b is arranged so as to be inclined with respect to the first direction by an angle −θ2. Here, as seen in the drawing, the clockwise direction will be referred to as a positive direction, and the counterclockwise direction will be referred to as a negative direction.
When seen in the first direction, the ink absorbing member 16a partly overlaps an end portion on the outer side of the first wiper blade 12a and the second wiper blade 13a, and wipes an outer region not overlapping the nozzle chips 20. When seen in the first direction, the ink absorbing member 16b partly overlaps an end portion on the outer side of the first wiper blade 12b and the second wiper blade 13b, and wipes an outer region not overlapping the nozzle chips 20.
As described above, with respect to one nozzle chip 20, the first wiper blade 12 is arranged so as to be inclined with respect to the first direction by the angle θ1 (θ1 is positive or negative). The second wiper blade 13 is arranged so as to be inclined with respect to the first direction by the angle θ2 (θ2 is positive or negative). In this exemplary embodiment, the absolute value of the angle θ1 is equal to the absolute value of the angle θ2. However, it is not absolutely necessary for the value to be equal to each other; the absolute values may differ from each other.
More specifically, the angle θ1 satisfies the condition: 0<θ1<arctan(2Y/H), and the angle θ2 satisfies the condition: −arctan(2Y/H)<θ2<0. The meaning of these formulas will be described below.
In one wiping operation, the set consisting of the first wiper blade 12, the second wiper blade 13, and the ink absorbing member 16 moves with respect to the surface of the nozzle chip 20 in the order: from
The first region reliably wiped by the first wiper blade 12 is a shaded region E1 in
If the angle θ1 and the angle θ2 do not satisfy the relationship as expressed by the above formulas but the absolute values of the angle θ1 and the angle θ2 become larger than arctan (2Y/H), the end portions of the central nozzle arrays (the second and third nozzle arrays in the present exemplary embodiment) get out of the shaded regions E1 and E2 and remain unwiped. When the arrangement number N of a nozzle array 21 is an odd number, the central nozzle array is the ((N+1)/2)th nozzle array.
Also regarding a region E4 (the nozzle surface region other than the region E1+E2), it can happen that the wiper blades are brought into contact therewith owing to deflection caused by elastic deformation, so that wiping can be expected to occur to some degree if not so reliably as in the case of the region E1+E2.
Suppose there is only one of the first wiper blade 12 and the second wiper blade 13. In the examples shown in FIGS. 10A and 10B, the end portion of the outermost nozzle array where movement is delayed gets out of the shaded regions E1 and E2 to remain unwiped. If the forward portion of the moving wiper blade climbs onto the sealing portion 23 protruding from the nozzle surface, the entire wiper is also raised. As a result, there remains an unwiped portion in a nozzle array. The farther a nozzle array is situated, the more it is subject to this phenomenon. Further, the larger the inclination angle, the greater the influence of this phenomenon. In view of this, in the present exemplary embodiment, next to the first wiper blade 12, the second wiper blade 13 of a reverse inclination angle is caused to pass, whereby it is possible to prevent generation of an unwiped region. In other words, a region where the wiping by the first wiping blade is incomplete is wiped by the second wiper blade.
Since the first wiper blade 12 is inclined with respect to the first direction, during the wiping movement, the ink and dust scraped off by the blade are gathered on the blade surface and move toward the upstream side with respect to the wiping direction along the blade surface. More specifically, they gradually move toward the outer ink absorbing member 16. The ink and dust having overflowed from the outer side of the first wiper blade 12 as a result of the movement adhere to the base substrate 24 on the outer side of the nozzle chip 20. However, the ink and dust having overflowed and adhering to the base substrate are absorbed and recovered by the ink absorbing member 16 coming and passing afterward. As a result, cleaning is performed on the entire recording head 2 without leaving any region unwiped. Since the ink absorbing member 16 does not come into contact with the nozzle surface, no ink or dust is allowed to adhere to the nozzle surface again.
Following the first wiper blade 12, the second wiper blade 13 passes, which also scrapes off the ink. However, most of the ink has already been wiped off by the first wiper blade 12, so that only a slight amount of ink gathers on the blade surface of the second wiper blade 13. Thus, virtually no ink overflows from the end portion (the inner side) of the second wiper blade 13 to adhere to the base substrate 24.
In the present exemplary embodiment described above, both the first wiper blade 12 and the second wiper blade 13 have a wiping width large enough to cover a plurality of nozzle arrays. However, if it is possible for the region E1+E2 shown in
In the present exemplary embodiment, two wiper blades (50a and 50b) are provided. The positional relationship between the wiper blades 50 and the ink absorbing members 16 is such that there is an interference amount of I2 with respect to the nozzle surface 22.
The wiper blade 50a is arranged so as to be inclined with respect to the first direction by an angle θ3. The wiper blade 50b is arranged so as to be inclined with respect to the first direction by an angle −θ3. As seen in the first direction, the ink absorbing members 16 partly overlap end portions on the outer sides of the wiper blades 50, and wipe the outer regions not overlapping the nozzle chips 20.
In the present exemplary embodiment, wiping is performed on the nozzle chips not with two wiper blades as in the above-described exemplary embodiment but with one wiper blade. Thus, there is a possibility of generating an unwiped region as described above. However, as described below, the range of the inclination angle θ3 is determined appropriately, whereby no region remains unwiped.
In
Also regarding a region E6 (the nozzle surface region other than the region E5), it is possible that the wiper blade is brought into contact therewith owing to deflection caused by elastic deformation, so that wiping can be expected to occur to some degree if not so reliably as in the case of the region E5.
Since the wiper blade 50 is inclined with respect to the first direction, during the wiping movement, the ink and dust scraped off by the blade are gathered on the blade surface and gradually move toward the outer ink absorbing member 16 along the blade surface. The ink having overflowed and adhering to the base substrate 24 is absorbed and recovered by the ink absorbing member 16 coming and passing afterward. As a result, cleaning is performed on the entire recording head 2 without leaving any region unwiped. Since the ink absorbing member 16 does not come into contact with the nozzle surface, no ink or dust is allowed to adhere to the nozzle surface again.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.
This application claims priority from Japanese Patent Application No. 2009-257419 filed Nov. 10, 2009, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2009-257419 | Nov 2009 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
5500660 | Childers et al. | Mar 1996 | A |
20050062796 | Mott et al. | Mar 2005 | A1 |
20070159508 | Yamamoto | Jul 2007 | A1 |
20080007592 | Watanabe | Jan 2008 | A1 |
Number | Date | Country |
---|---|---|
1518689 | Mar 2005 | EP |
08-001954A | Jan 1996 | JP |
2004-167928 | Jun 2004 | JP |
Number | Date | Country | |
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20110109691 A1 | May 2011 | US |