Electrophotography – Document handling – Copy
Reexamination Certificate
2000-05-02
2001-08-28
Pendegrass, Joan (Department: 2852)
Electrophotography
Document handling
Copy
C074S063000, C100S047000, C162S271000, C271S272000, C340S675000
Reexamination Certificate
active
06282403
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a setup and wear determination procedure and apparatus for a sheet decurler in an electronic reprographic image forming apparatus. The invention is particularly adapted for use and will be described in connection with the setting up and wear monitoring of a decurler that decurls paper or other image recording sheets by passing same between a relatively soft elastomeric roll and a relatively hard pinch or penetrating roll. Those of ordinary skill in the art will recognize that the invention has broader application, and it is not intended that the invention be limited to the particular environment disclosed herein. The invention has application to any nip-forming device including a pair of parallel rollers that must be precisely positioned relative to each other, and the rollers can also be equally hard or soft.
It is generally known to pass a sheet of paper or another image recording sheet through a nip defined between a relatively soft roll and a relatively hard roll (the hard roll is referred to herein as the pinch roll or penetrating roll), and to control the amount of sheet decurling by controlling the degree to which the pinch roll penetrates into the associated soft roll. In modern high-speed image forming apparatus, decurling assemblies of this type must be adapted for rapid and accurate adjustment of pinch roll penetration. Furthermore, even extremely small variances in pinch roll penetration can alter the amount of decurling. In one modern image forming apparatus, the entire penetration range, from a simple paper transport position (no sheet decurling) to a maximum decurling penetration (maximum sheet decurling) is encompassed by only 0.5 millimeters (mm).
Unfortunately, in manufacturing the pinch roll, the soft roll, associated mounting components, and the other components used to control the position of the soft roll relative to the pinch roll, and also in assembly, dimensional tolerances on these components “stack-up” and require a decurler setup procedure so that penetration amounts can be accurately controlled. That is, the position of the soft roll relative to the pinch roll must be exactly known in order to adjust same accurately to achieve the desired pinch roll penetration.
Furthermore, the soft roll is typically manufactured using an elastomer or the like, and abrasion caused by the driven pinch roll and by the sheets, themselves, results in significant wear. Without a periodic decurler setup procedure, the soft roll wear would quickly result in penetration errors and, ultimately, early replacement of the soft roll. Furthermore, a need has been identified for a method and apparatus for assessing the wear rate of the soft roll so that its eventual exhaustion can be predicted to an operator of the image forming apparatus so that a service call can be scheduled in advance.
SUMMARY OF THE INVENTION
The present invention is useful in a nip-forming apparatus including a first roll and a second roll, wherein one of the rolls is displaceable toward the other to control the position of the first roll relative to the second roll, and wherein one of rolls is driven and the other is rotatable. The invention defines a setup procedure comprising rotating the driven roll and sensing a rotational speed of the rotatable roll. While the driven roll is rotating, the displaceable roll is displaced to a home displacement position relative to the other roll, wherein the home displacement position corresponds to a displaced position of the displaceable roll where the rotatable roll rotates at a select speed in response to contact with the driven roll. This home displacement position is then recorded.
In accordance with another aspect of the present invention, a method of controlling a decurling apparatus that comprises a cylindrical pinch roll and a cylindrical second roll is defined. The method includes: (a) driving one of the rolls about a longitudinal axis; (b) moving one of the rolls into contact with the other of the rolls to a select home position where the driven roll contacts and rotates the other roll at a select speed; (c) recording the home position; (d) moving the rolls relative to the home position at least one of toward and away from each other to control an amount by which a harder one of the rolls penetrates a softer one of the rolls to control an amount of decurling in a sheet that passes between the rolls.
In accordance with yet another aspect of the invention, an apparatus for controlling a cylindrical pinch roll and a cylindrical second roll of a decurling apparatus is defined. The apparatus includes means for driving one of the rolls about a longitudinal axis, and means for moving one of the rolls into contact with the other of the rolls to a select home position where the driven roll contacts and rotates the other roll at a predetermined select speed. The apparatus further includes means for recording the home position, and means for moving the rolls relative to the home position at least one of toward and away from each other to control an amount by which a harder one of the rolls penetrates a softer one of the rolls to control an amount of decurling in a sheet that passes between the rolls.
One advantage of the present invention resides in the provision of a decurler roll setup procedure and apparatus.
Another advantage of the present invention is found in the provision of a method and apparatus for assessing the wear rate of the elastomer roll in a decurler and for predicting failure of the elastomer roll based upon the determined wear rate.
A further advantage of the present invention is the provision of a method for assessing the wear rate of the elastomer roll in a sheet decurler of an image forming apparatus, wherein the method includes warning an operator of the image forming apparatus in advance that a new elastomer roll will soon be required.
Still another advantage of the present invention is the provision of a decurler roll setup method and apparatus that result in improved quality sheet decurling due to more accurate pinch roll penetration control.
A still further advantage of the present invention resides in the provision of a decurler roll setup procedure and apparatus that extend the useful life of the elastomer roller in a sheet decurler by compensating for roll wear.
Still other benefits and advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following specification.
REFERENCES:
patent: 4632533 (1986-12-01), Young
patent: 5392106 (1995-02-01), Bigenwald et al.
patent: 5539511 (1996-07-01), Wenthe, Jr. et al.
patent: 3-259846 (1991-11-01), None
Buchman Leonid
Elliot Jack G.
Spencer Stan Alan
Fay Sharpe Fagan Minnich & McKee LLP
Pendegrass Joan
Xerox Corporation
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