Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-01-05
2003-04-01
Hsieh, Shih-wen (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S029000, C347S032000
Reexamination Certificate
active
06540320
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to ink jet and other types of printers and more particularly to a system and a method using a low-height service station design for servicing a printhead.
2. Related Art
Digital set-top boxes (e.g., cable television boxes, Internet terminal boxes etc.) are being used increasingly with consumer home entertainment equipment such as television sets, video cassette recorders, digital video disc (DVD) players and the like. In many cases, it may be desirable for users to obtain a hard copy of information displayed on the screen of their television sets. Specifically, users typically want to print e-mail messages, maps, recipes and information-rich content, such as still or captured scenes from live broadcasts, DVD players, movie cameras, video recorders etc.
Currently, if a user wants to have a hardcopy of the displayed information, the user has to use a conventional printer. Most conventional printers, however, are bulky, and thus require large amounts of space in users' home entertainment units. Hence, a printer specifically designed for use in home entertainment units is needed (i.e., a living room printer).
The living room printer should be of low height (i.e., low profile) and relatively narrow in width to blend in with other home entertainment equipment. In addition, since home entertainment equipment is usually stacked one atop another in home entertainment units, user access to the living room printer should preferably be through a front plane of the printer.
Designing a low profile, narrow width printer with user front plane access can present some technical difficulties with printers. For example, for ink jet printers, one common problem is that the ink nozzles of the ink jet printer frequently become plugged or otherwise contaminated with a variety of contaminants. For example, contaminants such as dried ink and foreign matter (such as paper fibers) can crust the nozzle both externally and internally. This can prevent the nozzles from operating properly and lower the quality of print. As a result, ink jet printers typically include a service station that services a printhead to keep the nozzles operating properly.
A typical function of the service station is called capping, which prevents the printhead from drying out when not in use. Capping uses a cap to provide a seal between the vaporization chamber and the printhead. Capping prevents ink from being drawn by capillary action from within the ink supply through the printhead. Another function of the service station is known as wiping, which uses a wiping action to remove external debris and contaminants from the nozzles. Ink used in ink jet printers is designed to dry quickly and permanently and, if allowed to dry on the nozzles and not wiped away, becomes difficult to remove.
Ink jet printer service stations may be implemented in a plurality of designs. For instance, one type of service station is a passive service station that does not use a motor. Passive service stations, however, are noisy and not very effective, which can lower print quality and shorten printhead life. Another type of service station design uses a motor to operate the service station and a separate motor to feed paper through the printer. There are several problems, however, with using a motor to feed the paper and a motor to operate the service station, including that the printer is more costly, complex and heavier (and thereby less portable) due to an additional motor and accompanying material.
Service stations are typically designed so that a platform that performs capping (a capping platform) and a platform that performs wiping (a wiping platform) are in close proximity, lie in the same plane and move together in that plane. This can cause ink to be dripped and splattered from the wipers onto the capping platform during the wiping action, thereby decreasing the effectiveness of the service station. In addition, service station designs generally are not greatly concerned with height constraints because the height of the printer, which generally is determined by the paper path, is more than enough to accommodate the service station. A printer having a lower height is desirable, however, because such a printer would easily fit into shelves and spaces used for other electronic equipment (such as VCRs and stereo equipment). Such a low-height printer would require a service station that is low-height, effective and efficient.
Therefore, what is needed is an ink jet printer having a low height that uses a single motor both to feed the paper through the printer and to operate the service station. What is also needed is a printer that includes capping and wiping platforms that do not operate in the same plane and move independently of each other to minimize the likelihood of ink residue from the wiping action contaminating the caps. Whatever the merits of the above-mentioned systems and methods, they do not achieve the benefits of the present invention.
SUMMARY OF THE INVENTION
To overcome the limitations in the prior art as described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention is embodied in a system and a method that uses a low-height service station design to service a printhead. The present invention uses a unique design to permit a single motor both to feed a print media through the printer and to operate the service station. Unlike other service station designs, the service station of the present invention includes a low-height profile, which enables the service station to be used with printers having a small vertical profile, and an independent lifting action for wiping and capping platforms, which prevents splattering of ink onto the caps during wiping operations. The present invention provides inexpensive, effective and simple servicing of a printhead.
The low-height service station design of the present invention includes a gear and clutch arrangement that permits a service station drive assembly and a print media feed assembly to use the same motor. Moreover, the gear and clutch arrangement provides a means for a capping platform and a wiping platform to move independently of each other. The capping platform includes a cap that is used in capping a printhead assembly and the wiping platform includes a wiper that is used to wipe the printhead assembly. Independent movement prevents the wiping platform from splattering ink onto the capping platform during wiping operations.
The present invention also embodied in a method for using a single motor to service a printhead assembly and feed a print media through a printer. The method includes disengaging an engaged print media feed assembly from the motor by momentarily reversing the direction of the motor, engaging a service station drive assembly, turning the motor in the forward direction so as to perform service station operations. The method also includes disengaging the service station drive assembly and engaging the print media feed assembly by momentarily reversing the motor direction. In a preferred embodiment, engagement of the motor is achieved using a clutch. Moreover, precise positioning of a capping platform and a wiping platform is achieved using a camshaft having a plurality of cams.
Other aspects and advantages of the present invention as well as a more complete understanding thereof will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. Moreover, it is intended that the scope of the invention be limited by the claims and not by the preceding summary or the following detailed description.
REFERENCES:
patent: 5841450 (1998-11-01), Kawamura
patent: 5971520 (1999-10-01), Nakahara
patent: 6027212 (2000-02-01), Tanno et al.
patent: 6132027 (2000-10-01), Suzuki et al.
patent: 6371595 (2002-04-01), Takemoto et al.
patent: 2-45156 (1990-02-01), None
patent: 6-262768
Hewlett--Packard Company
Hsieh Shih-wen
LandOfFree
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