Advancing material of indeterminate length – With material-responsive control means – To regulate longitudinal movement of material
Reexamination Certificate
1999-10-18
2001-08-28
Walsh, Donald P. (Department: 3653)
Advancing material of indeterminate length
With material-responsive control means
To regulate longitudinal movement of material
C226S016000, C226S021000, C226S042000, C226S074000, C226S095000, C226S111000
Reexamination Certificate
active
06279807
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a method and apparatus for transferring tractor pin feed hole-free web to and from a utilization device normally adapted to drive web using a tractor pin feed arrangement.
BACKGROUND OF THE INVENTION
In high volume printing applications, laser printers such as the IBM® 3800™ and 3900™ series, as well as the Siemens® 2140™, 2200™, and 2240™ series, lay down images on a continuous web by directing the web through an image element, that, typically, comprises a moving image drum having toner deposited thereon. A portion of such a web
12
is illustrated in FIG.
1
. The feeding of the web
12
to the image drum is facilitated by one or more “tractor pin” feed units that engage evenly spaced holes
14
disposed along opposing widthwise edges of the web on “pin feed” strips
16
. The widthwise edges having “tractor pin feed holes” therein, as well as the sheets themselves often include perforations
17
,
18
, respectively, for easy removal.
A typical pin feed application is depicted in
FIG. 2. A
source
20
of continuous web
22
is driven (arrow
24
) to an image transfer element
26
of a printer
28
. Toner
30
is provided to the image transfer element or drum
26
by operation of the optical print head
32
. A separate developer
34
is provided to attract the toner to the drum
26
. The web
24
engages the image drum
26
at a transfer station
36
where printing is laid upon the web as it passes over the image drum
26
. The image drum rotates (arrow
38
) at a speed matched to the speed of web travel. The web
24
is driven to and from the image drum
26
by a pair of tractor units
40
and
42
that each include a plurality of pins
44
on moving endless tractor beds
45
for engaging pin holes in the edges of the web. The pin holes
14
are detailed in
FIG. 1
discussed above.
Downstream of the tractor feed units
40
and
42
, the web
24
is directed over a fuser
46
and a preheat unit
48
that fixes the toner to the web
24
. The web is subsequently directed to a puller unit
50
that comprises a pair of pinch rollers and into a director chute
52
onto a stack of zigzag folded finished web
54
.
A significant disadvantage of a printer arrangement according to
FIG. 2
is that the additional inch to inch and one half of web that must be utilized to provide the tractor feed hole strips entails significant waste. The web area between the tractor feed pin hole strips already comprises a full size page and, thus, the tractor feed strips represent area having no useful function other than to facilitate driving of the web into the printer. In a typical implementation, the pin holes are subsequently torn or cut off and disposed of following the printing process.
A variety of utilization devices currently employ tractor pin feed continuous web. Such a feed arrangement is a standard feature on most devices that utilize more than 80 pages per minutes. Specialized equipment has been developed to automatically remove tractor pin feed strips when they are no longer needed. Hence, substantial cost and time is devoted to a web element that does not contribute to the finished appearance of the completed printing job. However, such tractor pin feed strips have been considered, until now, a “necessary evil” since they ensure accurate feeding and registration of web through a utilization device.
It is, therefore, an object of this invention to provide a reliable system for feeding continuous web through a utilization device that does not entail the use of wasteful edgewise strips having tractor pin feed holes.
It is another object of this invention to provide a system and method for feeding web that ensures accurate registration of the web with other moving elements of a utilization device and enables web to be directed to a variety of locations.
SUMMARY OF THE INVENTION
This invention relates to a system and method for utilizing web that is free of tractor pin feed holes. The system and method comprise the driving of the web along a predetermined path within the utilization device. A web guide is provided in an upstream location from a utilization device element. The guide engages width-wise edges of the web and forms the web into a trough to stiffen the web. A drive roller and a follower roller impinge upon opposing sides of the web and rotate to drive the web through the guide. The drive roller is located adjacent to the guide according to a preferred embodiment. A registration controller is utilized to synchronize the movement of the web with the operation of the utilization device element. The controller includes a drive controller that controls the speed of either the drive roller or the utilization device element to maintain the web and the utilization device element in appropriate synchronization.
In a preferred embodiment, the web guide can comprise tractor pin feed drive assemblies in which the tractor pins include plates that overly the tractor pins. In such an embodiment, web is held in place along its width-wise edges by the overlying plates and is retained against side-to-side movement by the tractor pins. The tractor pins engage the outer edges of the web (rather than holes formed in the edges of the web) and form the web into a trough that provides substantial beam strength to the web and enables accurate guiding of the web through the utilization device element. The drive roller can be located offset from a plane formed by the tractor pin belts to facilitate the formation of the trough.
The drive roller can be interconnected with the tractor pin feed drive element and operate in synchronization therewith. The follower roller of the drive roller can be provided with a pivotal bracket that allows the follower roller to be moved into and out of engagement with the drive roller so that web can be easily loaded onto the utilization device.
The utilization device element can comprise a rotating image drum according to a preferred embodiment and the utilization device can comprise a printer or copier adapted to feed continuous web. The registration controller, similarly, can comprise a sensor that senses a selected mark on the web such as a preprinted mark or a perforation. The controller can be adapted to scan for a mark at a selected time interval and modify the speed of the drive roller based upon the presence or absence of such a mark.
According to a preferred embodiment, the drive motor can include an advance and retard mechanism that is responsive to the controller to maintain the driven web in synchronization with the utilization device element. A registration drive motor and a differential gearing system can be provided to enable advancing and retarding of the drive roller. The drive element can comprise a harmonic drive differential.
The upper, downstream, tractor pin feed assembly of this invention can include a vacuum belt drive that prevents slippage of pinless web under tension applied by various components of the utilization device.
While the term “drive roller” is utilized according to this embodiment, it is contemplated that a variety of different driving mechanisms that enable advancing of a web to a utilization device element can be utilized according to this invention. It is of primary significance that such devices be capable at advancing a web that is free of tractor pin feed holes along the edges thereof or otherwise thereon. For example, a drive belt or belts can be substituted for the drive roller and the word “roller” is particularly contemplated to include such a belt or belts. Similarly, the drive can comprise a full-width roller or reciprocating foot or shoe that advances the web in selected increments.
REFERENCES:
patent: 2996951 (1961-08-01), Debrie
patent: 3209973 (1965-10-01), Eichorn
patent: 3466716 (1969-09-01), Hancock
patent: 3558109 (1971-01-01), Sofue
patent: 3588346 (1971-06-01), Ramig, Jr.
patent: 4243925 (1981-01-01), Gnuechtel
patent: 4297716 (1981-10-01), Hirayama et al.
patent: 4363270 (1982-12-01), Ury et al.
patent: 4461468 (1984-07-01), Peter, III et al.
pat
Bolza William F.
Crowley H. W.
Jackson Barry M.
Cesari and McKenna LLP
Loginov William A.
Rivera William A.
Roll Systems Inc.
Walsh Donald P.
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