Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-10-31
2004-05-18
Hsieh, Shih-Wen (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S029000, C347S033000
Reexamination Certificate
active
06736481
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to printing devices. More specifically, the present invention relates to capping systems and methods for capping ink ejection elements.
BACKGROUND OF THE INVENTION
Inkjet printing mechanisms, e.g., printers, photocopiers, facsimile machines, etc., typically implement inkjet cartridges, often called “pens” to shoot drops of ink onto a sheet of print media, e.g., paper, fabric, textile, and the like. Pens typically have multiple printheads that include very small nozzles on an orifice plate through which the ink drops are fired.
The particular ink ejection mechanism within the printhead may take on a variety of different forms as known to those skilled in the art, such as those using piezoelectric or thermal inkjet technology. To print an image, the printhead is scanned back-and-forth across a print zone above the sheet, with the pen shooting drops of ink as it moves. By selectively firing ink through the nozzles of the printhead, the ink is expelled in a pattern on the print media to form a desired image (e.g., picture, chart, text and the like).
The orifice plate of the printhead has a tendency to pick up contaminants, such as paper dust, dried ink and the like, during the printing process. Such contaminants may adhere to the orifice plate either because of the presence of ink on the printhead, or because of electrostatic charges. In addition, excess dried ink can accumulate around the printhead. The accumulation of either ink or other contaminants can impair the quality of the output by interfering with the proper application of ink to the print media. In addition, if color pens are used, each printhead may have different nozzles which each expel different colors. If ink accumulates on the orifice plate, mixing of different colored inks (cross-contamination) can result which may lead to adverse affects on the quality of the resulting printed product. Furthermore, the nozzles may become clogged, particularly if the printheads are left uncapped for a relatively long period of time. For at least these reasons, it is desirable to clear the printhead orifice plate of such contaminants on a substantially routine basis.
In this respect, servicing operations, including ink drop detections, wiping and capping of the orifice plate, and the like, are typically performed during, and/or after completion of the performance of a printing operation. In performing the servicing operations, inkjet printing mechanisms typically implement a service station located along the scanning direction. The service station is typically equipped with a plurality of components designed to carry out the servicing operations.
The wiper is designed to scrape off paper dust or other debris that may accumulate on the orifice plate as well as various other portions of the printheads. These wipers are typically made of a elastomeric material, for instance a nitrile rubber, ethylene polypropylene diene monomer (EPDM) elastomer, or other types of rubber-like materials. The wiping action is usually achieved by either moving the printhead across the wiper, or moving the wiper across the printhead. Unfortunately, such wiping operations have oftentimes been found to be inadequate to effectively remove paper dust and other debris. In addition, such wiping actions may cause excess ink to build up on the lower side portions of the printheads as well as degradation of the wiper itself. Furthermore, ink may become dried on the surface of the wiper and may cause it to become less effective.
The capping operation is typically performed through use of a cap. The cap is normally composed of a substrate that supports a seal for humidically sealing the printhead nozzles from contaminants and drying. Typically, the seal is an elastomeric enclosure having sealing lips which surround the nozzles and form an air-tight seal at the printhead face (i.e., nozzle plate). The cap is typically maneuvered into position on the printhead through vertical motion of the cap from the service station. The cap is not equipped to clean off the nozzle plate or the printhead but merely provides a seal to protect the nozzles.
SUMMARY OF THE INVENTION
According to a preferred embodiment, the present invention pertains to a system for cleaning an ink ejection element having a plurality of nozzles. The system includes a device having a substrate supporting at least one absorbent pad located at a first location on the substrate. The first location corresponds to a second location on the ink ejection element and the second location is free of the plurality of nozzles. In this respect, the at least one absorbent pad is substantially prevented from contacting any of the plurality of nozzles.
According to an aspect, the present invention relates to a method of cleaning ink ejection elements of an image forming mechanism having a plurality of nozzles. In the method, a device having at least one absorbent pad is maneuvered in a substantially vertical direction towards a bottom surface of the image forming mechanism. The at least one absorbent pad is contacted with a predetermined location on the image forming mechanism when the device is substantially close to the image forming mechanism to thereby remove debris from the image forming mechanism. In addition, the predetermined location does not include any of the plurality of nozzles.
According to another aspect, the present invention pertains to an image forming mechanism. The mechanism includes an ink ejection element having a plurality of nozzles. The ink ejection element is configured to undergo cleaning operations at a service station. The service station includes a wiper for selectively wiping the ink ejection element and a carriage movably supporting a cleaning device. The cleaning device includes at least one absorbent pad. The at least one absorbent pad is positioned on the cleaning device to substantially prevent contact with any of the plurality of nozzles when the ink ejection element is cleaned with the cleaning device.
In comparison to known printing mechanisms and techniques, certain embodiments of the invention are capable of achieving certain advantages, including, little to no risk of scratching or otherwise damaging the nozzles of ink ejection elements with the absorbent pads, placement of the absorbent pads generally enables removal of waste ink and other debris at selective locations on the ink ejection elements, the absorbent pads may be utilized for relatively long periods of time by virtue of the lack of relative sliding movement between the absorbent pads and the ink ejection element, and the embodiments of the present invention may be implemented in conjunction with pre-existing capping systems in a relatively simple manner. Those skilled in the art will appreciate these and other advantages and benefits of various embodiments of the invention upon reading the following detailed description of a preferred embodiment with reference to the below-listed drawings.
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patent: 5552811 (1996-09-01), Kurata et al.
patent: 5635965 (1997-06-01), Purwins et al.
patent: 5694157 (1997-12-01), Ahlvin
patent: 5997128 (1999-12-01), Lou et al.
patent: 6155667 (2000-12-01), Eckard et al.
patent: 0 744 294 (1996-11-01), None
patent: 4-338552 (1992-11-01), None
Gaston Gonzalo
Monclus Antonio
Urrutia Martin
Hewlett-Packard Development Company LP.
Hsieh Shih-Wen
LandOfFree
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