Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2002-08-01
2003-07-01
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
Reexamination Certificate
active
06585368
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to printer devices. More particularly, the invention relates to a gear clutch assembly and method for operating a transfix roller and a drum maintenance system using a single motor without electromagnetic solenoids or clutches and will be described with particular references thereto. However, it is to be appreciated that the present invention may also be amendable for other applications.
In many print devices, an intermediate transfer surface, such as a transfer drum, is used to deliver printer ink from a print head to a print or receiving medium such as paper. More specifically, ink is ejected from jets in the print head onto the transfer drum creating a liquid layer of ink. The receiving medium is then brought into contact with the transfer drum and the ink image is transferred and fused or fixed to the receiving medium.
To assist in the transfer and fixing of the ink image, a transfix roller is often utilized to apply a pressure to the receiving medium thereby pressing the receiving medium against the transfer drum. When or around the time the receiving medium engages the transfer drum for transfixing of the image on the receiving medium, the transfix roller is moved from an idle unloaded or disengaged position toward a loaded or engaged position. In the loaded position, the receiving medium is sandwiched between the transfer roller and the transfer drum. After the ink image is transfixed on the receiving medium and the receiving medium is ready or about ready to disengage from the transfer drum, the transfix roller is moved from the loaded position toward an unloaded position to permit the receiving medium to exit from the transfix roller and transfer drum. The transfix roller remains in the unloaded position until the next transfix operation occurs.
After the ink is transfixed to the receiving medium from the transfer drum, the transfer drum requires conditioning for a subsequent ink jetting from the print head. Typically, a drum maintenance system is used to condition the transfer drum for receipt of the next ink image. The drum maintenance system, when activated, moves from an idle or disengaged position to an operating or engaged position. In the engaged position, a roller included in the drum maintenance system applies an oil or other similar functioning substance to the transfer drum. The oil reduces the probability that ink sprayed onto the transfer drum will stick to the transfer drum during the transfix operation. The drum maintenance system also includes a plastic or rubber blade that approaches or engages the transfer drum when the drum maintenance system is in the engaged position. The blade meters the oil being applied to the transfer drum. While the drum maintenance system is in the engaged position, the transfix roller remains in its idle unloaded position. Upon completion of the drum maintenance operation, the drum maintenance system is moved to its idle position.
Typically, the transfix roller and the drum maintenance system are cam driven. That is, each of the transfix roller and the drum maintenance system are driven by independent cam mechanisms, a transfix cam mechanism and a drum maintenance cam mechanism. The prior art generally recognizes two systems or methods of operating the transfix roller and drive maintenance system cam mechanisms. First, two separate motors may be used. The first motor would drive the transfix cam mechanism and the second motor would drive the drum maintenance cam mechanism. A disadvantage of the two motor system is the cost for including two such motors in a print device and the spacial and volumetric constraints of print devices.
In the second prior art system, a single motor is used to drive both the transfix cam mechanism and the drum maintenance cam mechanism. Independent control of the cam mechanisms is achieved through the use of electromagnetic clutches or electromagnetic solenoids. There are several disadvantages in the single motor/electromagnetic clutch or solenoid system. First, electromagnetic clutches and solenoids are unreliable as they tend to fail and render their print devices inoperable. Second, although not always as costly as the two motor system, electromagnetic clutches and solenoids are still costly to include in competitive print devices. Third, single motor/electromagnetic clutch or solenoid systems do not permit operation of the cam mechanisms simultaneously. Simultaneous or concurrent operation allows the drum maintenance system to be moved toward the engaged position at the same time that the transfix roller is moved from the loaded position to the unloaded position. Such simultaneous operation increases the speed and efficiency of the print device. Thus, there is a need to provide a single motor system in a print device that will independently operate a transfix roller and a drum maintenance system via a pair of cam mechanisms. Such a system should permit concurrent operation of the transfix roller and the drum maintenance system while reducing reliability issues and cost implications.
The present invention provides a new and improved gear clutch assembly and method for operating a transfix roller and a drum maintenance system within a print device for overcoming the above-referenced drawbacks and others.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, a gear assembly for a print device is provided. More particularly, in accordance with this aspect of the invention, the gear assembly includes an input gear connected to a drive shaft of a motor. The gear assembly further includes a first output gear and a second output gear. The first output gear operates a transfix roller in the print device and is spaced relative to the input gear to allow teeth of the input gear to mesh with teeth of the first output gear. The first output gear includes a first toothless portion that does not mesh with teeth of the input gear when the input gear is adjacent the first toothless portion. The second output gear operates a drum maintenance system in the print device and is spaced relative to the input gear to allow teeth of the input gear to mesh with teeth of the second output gear. The second output gear includes a second toothless portion that does not mesh with teeth of the input gear when the input gear is adjacent the second toothless portion.
The gear assembly further includes a swing arm for rotating the first output gear when the input gear is adjacent the first toothless portion and the second output gear when the input gear is adjacent the second toothless portion. Said rotation of the first output gear moving the first toothless portion away from the input gear and allowing teeth of the input gear to engage teeth of the first output gear. Said rotation of the second output gear moving the second toothless portion away from the input gear and allowing teeth of the input gear to mesh with teeth of the second output gear.
According to another aspect of the present invention, a new and improved print device is provided. More particularly, in accordance with this aspect of the invention, the print device includes a transfer drum for transferring an image to a print medium and a transfix roller for applying a pressure on the print medium against the transfer drum. The print device further includes a drum maintenance system for preparing the transfer drum for subsequent image transfers to the print medium. A first cam assembly is provided for moving the transfix roller between a loaded position where pressure is applied to the print medium against the drum and an unloaded position. A second cam assembly is provided for moving the drum maintenance system between and engaged position wherein the drum maintenance system is capable of preparing the transfer drum for a subsequent image transfer and an idle position.
The print device further includes a single-motor and gear arrangement for selectively moving the first and second cams to control the transfix roller and the drum maintenance system. The arrangement includes a motor havi
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