Typewriting machines – Sheet or web – Including skew correction responsive to position of sheet or...
Reexamination Certificate
1999-09-17
2001-10-23
Hilten, John S. (Department: 2854)
Typewriting machines
Sheet or web
Including skew correction responsive to position of sheet or...
C226S031000
Reexamination Certificate
active
06305857
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, high-volume electronic or “laser” printers such as the IBM® 3800™ and 3900™ series, as well as the Siemens® 2140™, 2200™, and 2240™ series, lay down computer-generated images (at a rate of 100 or more standard images per minute) 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 dpicted 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. This is often accomplished by gearing or drive belts that interconnect the tractor pin feed units
40
,
42
and the drum to a central drive motor. 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 belts
45
for engaging pin holes in the edges of the web. The pin holes
14
are moving endless tractor belts
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 pin 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 challenge in modifying existing tractor pin feed utilization devices, such as the high-volume IBM® 3900 Series laser printer illustrated in
FIG. 2
is that a number of sensor signals rely upon the scanning of tractor pin feed holes. For example, the fuser section
46
draws the web from the drive section of the image drum
26
at a relatively synchronized rate. In order to maintain synchronization, and to ensure that the side edges of the web do not move laterally, electro-optical advance sensors and skew sensors are used adjacent the fuser section. These sensors scan for the location of tractor pin feed holes. The holes are required to operate these sensors. However, when holes are absent, an alternate sensing arrangement must be utilized.
In a pinless drive of web through a portion of a utilization device it may be desirable to provide correction to the feed rate of the web to maintain the web relative to the image drum or other utilization drive element. Registration can be controlled by providing a differential drive to the main pinless drive element when an offset in proper registration is deleted. However, the offset may be significant enough that the input registration correction by the differential drive may cause a sudden “jump” discontinuity in the web. Particularly where toner is laid down by an image drum this discontinuity of the applied image.
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.
It is a further object of this invention to provide a system and method of feeding pinless web particularly through a utilization device having a fuser section with a separate fuser section with a fuser motor downstream of an image drum drive section. The system and method should ensure adequate registration between each section in the absence of pin feed holes to enable registration serving.
It is a further object of this invention to provide registration control to a drive for pinless web in a utilization device that evenly applies registration control evenly over a web section to avoid abrupt registration correction that could cause discontinuities.
SUMMARY OF THE INVENTION
This invention relates to a system and method for utilizing a continuous pinless web that is free of tractor pin feed holes within a utilization device that is originally adapted to feed web having tractor pin feed hole strips along its widthwise edges is provided. The utilization device can comprise an IBM high-volume laser printer, capable of printing 100 or more standard pages of images per minute, and having an image transfer drum synchronized to a pair of tractor pin feed drive units. A drive roller is operatively connected to the lower pin feed unit 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 using a differential and a separate registration motor. The image transfer drum and drive roller are each synchronized to a central drive motor that generates pulses via an encoder. The pulses track the movement of the image transfer drum. A mark sensor reads marks on the web to synchronize actual movement of the web with the image transfer drum using the registration motor. The movement of the registration motor is averaged over the length of each section or page in the web to avoid jump discontinuities. The printer's fuser section draws web from the image transfer element at a controlled rate and with a desired steering alignment. Signals that emulate those originally generated by a hole tracking skew/advance/retard sensor are generated by comparing fuser drive pulses to drive motor pulses and monitoring the location of the pinless web edge as it passes under a dedicated edge location sensor.
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 wi
Bolza William F.
Clifford John W.
Crowley H. W.
Hetenyi Tamas
Sjostedt Richard A.
Cesari and McKenna LLP
Hilten John S.
Loginov William A.
Nolan, Jr. Charles H.
Roll Systems Inc.
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