The operation of inkjet printers sometimes results in unwanted excess ink accumulating on the printhead(s) in areas around the ink ejection orifices. Such ink accumulation may interfere with accurate ink drop ejection or otherwise adversely affect print quality. Servicing to remove excess ink from a printhead often involves wiping the orifice plate and adjacent areas with a flexible blade or other suitable wiper. The wiper moves back and forth across the orifice plate and adjacent areas, removing excess ink to areas away from the orifice plate. Wiper servicing, however, can leave waste ink accumulations at the perimeter of the wiper path still in close proximity to the print zone. After extended use this waste ink may build-up in sufficient quantity to droop or dislodge onto or otherwise contact the print media, resulting poor quality printed output.
Embodiments of the disclosure were developed in an effort to remove waste ink from the wiper during wiper servicing of an inkjet printhead and to keep the unwanted waste ink away from the print zone. Embodiments will be described with reference to an inkjet printhead assembly that holds replaceable ink containers. Embodiments of the disclosure, however, are not limited to such printhead assemblies, but might also be implemented in other types of printhead assemblies or ink cartridges, specifically including but not limited to ink cartridges in which the printhead assembly and the ink container are integrated into a single unit/cartridge. The use of inkjet technology for dispensing fluids other than ink is growing. Embodiments of the disclosure are also not limited to inkjet printer components, but might also be implemented in other types of fluid dispensing components. The example embodiments shown in the Figures and described below, therefore, illustrate but do not limit the scope of the disclosure.
As used in this document, “bumper” means something configured to bump or be bumped. Any directional terms such as “up” and “down”, “left” and “right”, “top” and “bottom”, etc., are used with reference to the orientation of the component being described as shown in the applicable figure(s). Such components, however, may be oriented differently from that shown and, therefore, directional terms are used for illustration only and do not limit the scope of the disclosure.
In the embodiment shown, each array 48 is a single row of orifices 50. Also in the embodiment shown, printhead assembly 26 includes two orifice plates 46, each corresponding to a printhead 40 associated with each ink container 30 and 32. In one such dual printhead configuration, ink container 30 might contain three different colored inks, typically cyan, magenta and yellow, and ink container 32 might contain a single colored ink, typically black. Each printhead 40 may be constructed separately as a discrete die or the two printheads 40 may be constructed as an integral unit on a single die. Other configurations are possible. For example, orifice rows 50 could be staggered and a separate container used for each color ink.
In a thermal inkjet printer, firing resistors formed on an integrated circuit chip as part of each printhead 40 are positioned behind orifice plate 46. A flexible circuit 52 carries electrical traces from external contact pads 54 to the firing resistors. When printhead assembly 26 is installed in printer 10 (
Referring now also to the detail views of
A wiper bumper 58 extends across one side 60 of body 42 at one end of face 56. Side 60 is generally perpendicular to face 56. Although side 60 may intersect face 56 at other angles, more or less than 90°, the problem of handling waste ink is more difficult when side 60 and face 56 intersect one another at a relatively sharp corner, as is quite common. A contoured rail 61 across the end 62 of face 56 may be used to help protect the edge of flex circuit 52 and to provide a smooth transition for wiper 36 (
Bumper 58 may be a separate part affixed to assembly body 42, as shown in
It is desirable to size and shape bumper 58 so that: (1) inclining exterior surface lower part 70 moderates the otherwise abrupt edge at the end of face 56 as wiper 36 moves to the left in
The location and shape of the print media is usually well controlled by feed/pinch rollers so that it remains flat as it enters the print zone and begins to pass under face 56, but may not remain flat at the end of the print zone opposite the pinch rollers. (The print media passes under face 56 moving from right to left in FIGS. 2 and 4-7.) The pinch rollers contact dry media just upstream from the print zone while at the other end of the print zone the printed media may be heavily wetted with ink and can swell and cockle (undulating wrinkles). Additionally, the shape and location of the wetted print media at the end of the print zone opposite the pinch rollers is more difficult to control. Thus, it is more likely the print media will contact any waste ink which, in the absence of bumper 58, could accumulate along the lower edge of side 60. Bumper 58 helps prevent waste ink from accumulating along the lower edge of side 60. The action of wiper 76 on bumper surface parts 70 and 74 helps keep ink from accumulating on those surfaces, reducing the risk of waste ink contacting print media in the print zone.
In the embodiment shown in
The present disclosure has been shown and described with reference to the foregoing example embodiments. It is to be understood, however, that other forms, details and embodiments may be made without departing from the spirit and scope of the disclosure which is defined in the following claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2008/054004 | 2/14/2008 | WO | 00 | 7/14/2010 |
Publishing Document | Publishing Date | Country | Kind |
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WO2009/102333 | 8/20/2009 | WO | A |
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Number | Date | Country | |
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20110115851 A1 | May 2011 | US |