Sheet feeding or delivering – Feeding – With means to align sheet
Reexamination Certificate
2002-10-08
2004-11-16
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
With means to align sheet
C271S227000, C271S259000
Reexamination Certificate
active
06817609
ABSTRACT:
Cross-referenced is U.S. patent application Ser. No. 10/237,362 filed Sep. 6, 2002 by the same inventors, and having the same assignee, entitled “Printer Lateral and Deskew Sheet Registration System.”
In the exemplary and various other sheet handling devices and systems, accurate registration of the sheets is accomplished through various mechanisms and methods which require normal sheet feeding nips to open. Upon opening the sheet feeding nips, the sheet is released therefrom so that a sheet registration device is able to orient the paper. In previous designs, relatively complex and expensive solenoid driven or stepper motor driven mechanisms typically accomplished these nip openings by mechanical movement of idlers away from their drive rolls. The system and method of the disclosed embodiment eliminates such complex and expensive mechanisms associated with previous nip opening systems.
The disclosed embodiment is also an improvement over the system and method of Xerox Corp. U.S. Pat. No. 6,168,153 issued Jan. 2, 2001 to Paul N. Richards, et al, and others cited herein.
With the specific embodiment disclosed herein, a separate motor or solenoid is not required to open the upstream paper path sheet feed roller nips by moving the idlers away to allow for longer sheet deskewing and/or side registration (lateral registration) in the downstream sheet lateral registration system. The same stepper or servo motor that is used for driving the sheet feed rollers can be used. It can be simply controlled in its rotational position to selectively hold open the upstream sheet feeding nips that need to be held open for the deskewing and/or side registration of that particular sheet. Also, the mating idlers can be conventionally fixedly mounted (for further cost reductions).
This is enabled in this disclosed embodiment by larger circumference sheet feed rollers having at least two different radii (which for simplicity of description may be referred to herein as “D” rollers). Plural sets of these upstream “D” feed rollers selectively provide, with selected partial rotations, either normal sheet feeding nips or open nips allowing unobstructed variable size sheet lateral movement therein by the downstream sheet lateral registration system yet positive sheet feeding and control.
Further by way of background, various sheet lateral registration systems are known in the art, and the present system is not limited to any particular sheet deskew and/or side-shifting system. The above-cited U.S. Pat. No. 6,168,153 shows one type. The specific example schematically shown herein is one of various known TELER systems of sheet registration, which also have differential roll pair driving for sheet deskew, and in which sheet side-shifting is also provided. The sheet lateral (side-shift) registration may be accomplished in a TELER system by side-shifting the TELER sheet drive rolls and their associated components while the sheet is engaged in the feed nip of those TELER sheet drive rolls. That sheet side-shifting can provide lateral sheet registration in a known manner, as by a carriage containing the two drive rollers, and their opposing nip idlers, being axially side-shifted to side-shift a nip-engaged sheet into lateral registration. Sheet process direction registration can also be provided by the controlled common forward driving rotational velocity of the same pair of rollers.
Examples of such TELER systems include U.S. Pat. No. 5,094,442, issued Mar. 10, 1992 to Kamprath et al; U.S. Pat. Nos. 5,794,176 and 5,848,344 to Milillo et al; U.S. Pat. No. 5,219,159, issued Jun. 15, 1993 to Malachowski and Kluger (citing numerous other patents); U.S. Pat. No. 5,337,133; and other cited patents. Of interest is a Xerox Corp. U.S. Pat. No. 5,278,624, issued Jan. 11, 1994 to David R. Kamprath and Martin E. Hoover, showing another example of a TELER type of combined lateral sheet registration and deskewing system for a printer, but with only a single drive motor and reduced mass of the TELER lateral translation (side shifting) components. Reduced mass is helpful both for allowing more rapid or lower power side-shifting and the re-centering or return to a “home” position of TELER systems. Heretofore the latter has been done in the very short time and space available only between successive sheets in the sheet path of a high speed printer, i.e., when no sheet is in the nip of the TELER system.
Of particular background interest is a Xerox Corp. U.S. Pat. No. 5,078,384 issued Jan. 7, 1992 to Steven R. Moore. This is not a TELER system. Rather, it accomplishes sheet deskewing and downstream or forward direction registration by differential driving of two sheet drive rolls
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, by two servomotors, but does not provide sheet lateral (sideways) registration by any side-shifting of those drive rolls. Thus, it does not teach or suggest (or even have the problem of) accomplishing rapid re-centering of a TELER system in between operative sheet nip engagements. However, this U.S. Pat. No. 5,078,384 does show the use of “D” shaped (partially relieved radius) drive rolls
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to disengage those drive rolls from the sheet (opening the drive nip) when those drive rolls are rotated to the position in which the reduced radius or “flat” portion of those “D” shaped drive rolls is facing the sheet and becomes spaced therefrom due it the reduced radius of that portion of the roll.
“D” shaped sheet feeding rolls are, of course, used in various other paper sheet feeding applications. For example, Xerox Corp. U.S. Pat. No. 5,449,165, issued Sep. 12, 1995, discloses a 90 degree paper feed transition module with transversely mounted and intermittently rotated “D” shaped feed rolls. Xerox Corp. U.S. Pat. No. 4,929,128, issued May 22, 1990 to Stemmle, shows typical segmented or “D” shaped feed rolls for initial sheet feeding, and for duplex path sheet feeding. However, the present embodiment provides normal and even closed nip sheet nip engagement and feeding, unlike such “D” roller sheet feed systems in which a stationary sheet is unevenly accelerated by initial engagement of a “corner” of the “D” roller (where the “D” roller transitions from it's smaller to it's larger radius) with the sheet.
Disclosed in the embodiment herein is an improved system for controlling, correcting and/or changing the position of sheets traveling in a sheet transport path, in particular, for rapid automatic sheet skew correction and/or side registration of a wider range of different sizes of paper or other print media sheets in or for an image reproduction apparatus, such as a high speed electronic printer, to provide deskewing and/or side registration of much longer sheets without losing positive sheet feeding control over much shorter sheets, including subsequently fed sheets in the sequence of sheets in the sheet path. This may include deskewing and/or side registration of sheets being initially fed in to be printed, sheets being recirculated for second side (duplex) printing, and/or sheets being outputted to a stacker, finisher or other output or module.
More specifically disclosed in the embodiment herein is an improved system and method for automatically engaging and disengaging an appropriate number of sequential plural spaced sheet feed-in nips of the sheet transport in the sheet path into the sheet deskewing system in accordance with a control signal corresponding to the length of the sheet to be laterally registered. The sheet “length” here is the sheet dimension in the sheet feeding or sheet movement direction of the sheet path, otherwise known as the “process direction,” as such terms may be used in the art in that regard, even though, as is well known, smaller sheets are often fed “long edge first,” rather than lengthwise, whereas in contrast very large sheets are more often fed lengthwise. Sheet “width” as referred to herein is thus the orthogonal sheet dimension as the sheet is being fed, i.e., the sheet dimension transverse to the sheet path and the sheet movement direction.
As shown in the embodiment example, these features and
Halvonik Mark R.
Herrmann Douglas K.
Joerger Kaitlin
Walsh Donald P.
Xerox Corporation
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