Information
-
Patent Grant
-
6598869
-
Patent Number
6,598,869
-
Date Filed
Wednesday, July 18, 200123 years ago
-
Date Issued
Tuesday, July 29, 200321 years ago
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Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 271 26501
- 271 26502
- 271 315
- 271 317
- 399 16
- 700 228
- 700 229
- 700 230
- 198 572
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International Classifications
-
Abstract
A method of media handoff from a first device to a second device comprises transmitting a first signal from the first device indicating a medium is at a predetermined handoff point. The first device receives a second signal from the second device instructing the first device to transport the medium toward the second device. The first device transports the medium toward the second device and receives a third signal from the second device indicating acceptance of the medium by the second device.
Description
FIELD OF THE INVENTION
The invention relates to media handling devices. In particular, the invention relates to a protocol for media handoff between devices using either continuous or indexed feed.
BACKGROUND
For a processing medium such as paper, the medium may be transported through several media handling devices in a media path. Each of the devices in a media path is provided with a media driver such as rollers. Such media handling devices may include printers, fax machines, scanners, or a variety of other such devices. Typically, the devices are placed substantially adjacent to each other in the media path, allowing automatic handoff from the output of one device to the input of the next device.
Typically, media handling devices in a media path process media in a continuous mode. In such a mode, when one device outputs a medium, the next device in the path accepts that output and continues transporting the medium in a continuous manner. Once the second device begins the process of receiving the medium, no further communications are made between the two devices. Thus, the next device continues to process the medium, and no interruptions in the movement of the medium are allowed. An example of a continuous-mode device is a laser printer. Laser printers process a medium as it continuously moves through the device.
However, a media path may contain a device that requires indexed movement, rather than continuous movement. An example of such a device is an ink jet printer. An ink jet printer typically periodically moves the medium a predetermined amount during the printing operation. While the medium is stopped, the ink jet printer prints on a section of the medium before again moving the medium a predetermined amount. Existing media handling systems do not accommodate handoff between two devices in a media path if one or more of the devices requires indexed movement.
During a handoff, the last set of rollers of one device and the first set of rollers of the next device in the media path typically have control of the media simultaneously for at least some period of time. Certain devices may have releasable rollers that can release the medium once the next device has the medium between its rollers. Thus, once the next device has the medium between its rollers, it transports the medium with no assistance from the previous device. Such operation is hereinafter referred to as “no-assist operation”.
Certain devices, however, may not have releasable rollers and may maintain some control over the movement of the medium even after the next device has the medium between its rollers. Thus, the medium may simultaneously be under the control of two separate devices. Such operation is hereinafter referred to as “assisted operation”.
The invention provides a handoff protocol that is capable of accommodating handoffs requiring indexed feed. In additional embodiments, the invention provides a protocol which also accommodates continuous-feed handoffs and handoffs with no-assist or assist operation.
SUMMARY OF THE INVENTION
One embodiment of the invention provides a method of media handoff from a first device to a second device comprising transmitting a first signal from said first device indicating a medium at a predetermined handoff point; receiving a second signal from the second device instructing the first device to transport the medium toward the second device; transporting the medium toward the second device; receiving a third signal from the second device indicating acceptance of the medium by the second device; receiving a fourth signal from the second device instructing the first device to transport the medium a predetermined distance; and transporting the medium the predetermined distance.
According to another embodiment of the invention, a media handoff system comprises a first media handling device comprising a first media driver for transporting a medium through the first media handling device and a first controller for controlling the first media driver; and a second media handling device comprising a second media driver for receiving the medium from the first media handling device and transporting the medium through the second media handling device and a second controller for controlling the second media driver and being adapted to communicate with the first controller; wherein the first controller is adapted to receive signals from the second controller and to start or stop the first media driver in response to the signals.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, the invention will be explained in further detail with reference to the drawings, in which:
FIG. 1
is a schematic diagram of a media handling system according to one embodiment of the invention;
FIG. 2
is a schematic diagram of the operation of a media handling system using indexed feed with no assist;
FIG. 3
is a schematic diagram of the operation of a media handling system using indexed feed with assist;
FIG. 4
is a schematic diagram of the operation of a media handling system using continuous feed with assist; and
FIG. 5
is a schematic diagram of a media handling system according to another embodiment of the invention.
DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION
FIG. 1
illustrates a media handling system capable of operating according to an embodiment of the invention. The media handling system
100
includes a first media handling device
110
and a second media handling device
120
. The media handling devices
110
,
120
are located close enough to each other to allow handoff of a medium
190
, such as paper, mylar or any other convenient medium, from one media handling device to the other. The medium
190
has a leading edge
192
and a trailing edge
194
, with the medium
190
being transported in the example from left to right in
FIG. 1
, as indicated by the arrow
199
. Thus, medium
190
is handed off from the first media handling device
110
to the second media handling device
120
.
Media handling device
110
is provided with a drive mechanism such as exit rollers
112
driven by a motor or other means to transport the medium
190
. In one embodiment the exit rollers
112
may be the last set of rollers in a series of roller sets in media handling device
110
. The exit rollers
112
may be releasable so that they may disengage the medium
190
. The media handling device
110
also has a controller
115
for controlling the rollers
112
and other aspects of the media handling device
110
such as communication with other devices. Note that the drive mechanism is not limited to rollers, and may take a variety of other forms including air drives, magnetic drives, electrostatic drives and any other convenient drive mechanisms.
The second media handling device
120
has a drive mechanism such as driven entry rollers
122
for receiving the medium
190
. In one example, the entry rollers
122
may be the first in a series of roller sets of media handling device
120
. The media handling device
120
also has a controller
125
for, among other functions, controlling the movement of the rollers
122
. Note that other drive mechanisms may be used in place of the rollers, as noted above.
A communication link
150
is provided between the controller
115
of the first media handling device
110
and the controller
125
of the second media handling device
120
. The communication link
150
may take the form of a wire, network connection, or an RF or other signal. Thus, the controllers
115
,
125
are capable of communicating with each other via communication link
150
. Initially, when a media handling device becomes aware of an approaching medium, it may transmit a “PAGE ANNOUNCE” signal alerting other devices in the media path. For example, prior to the beginning of a handoff, the first handling device
110
may transmit a message to the second media handling device
120
. This message may be used for a variety of purposes, including to allow the second media handling device to begin, for example, a warm-up process in preparation for the incoming medium and may allow tailgating of media (i.e., processing media as closely as possible to one another).
FIG. 2
illustrates the operation of a media handling system similar to that illustrated in
FIG. 1
, but using an indexed feed in a no-assist operation. As noted above, indexed feed is required for many devices such as ink jet printers. Such devices require one or more start/stop operations for processing of the media. During a no-assist operation, the upstream device in the handoff has releasable rollers that release the medium when the downstream device has the medium under its control.
Referring now to the operation illustrated in
FIG. 2
, a series of signals is transmitted between the controllers of the two media handling devices
110
,
120
. The operation begins when the leading edge
192
of the medium
190
reaches a predetermined handoff point of the first media handling device
110
. This point is typically slightly downstream of the last set of rollers or other drive mechanism of the device
110
. In
FIG. 2
, this point is illustrated by reference numeral
299
. When the controller
115
of the first media handling device
110
determines that the leading edge
192
of the medium
190
has reached the handoff point
299
, the controller
115
transmits a “MEDIA AT HANDOFF” signal
210
to the controller
125
of the second media handling device
120
. Note that this determination may be made in any convenient manner, such as for example, through the use of one or more media sensors at or adjacent the handoff point
299
. The media sensors may take several forms including optical detectors. When the media handling device
120
is ready for the medium
190
to be fed to its entry rollers
122
, it transmits a “READY TO ACCEPT” signal
220
to the controller
115
of the media handling device
110
. The controller
115
then causes the exit rollers
112
to transport the medium
190
toward the second media handling device
120
and transmits a “READY TO RELEASE” signal
230
to the controller
125
of the media device
120
.
When the controller
125
of the second media handling device
120
determines that the medium
190
has been received by the entry rollers
122
of the second media handling device
120
, it transmits a “MEDIA ACCEPTED” signal
240
to the controller
115
of the first media handling device
110
. Note again that the determination can be performed in any convenient manner, including by the use of one or more sensors. The controller
115
then causes the releasable exit rollers
112
to release the medium
190
. The controller
115
then transmits a “MEDIA RELEASED” signal
250
to the controller
125
of the second media handling device
120
. Once the medium
190
is released by the first media handling device
110
, the second media handling device
120
begins processing of the media under its exclusive control. Thus, media movement through the first media handling device
110
and the second media handling device
120
may be indexed.
FIG. 3
illustrates the operation of a media handling system similar to that illustrated in
FIG. 1
using an indexed feed in an assisted operation. Assisted operation requires two or more devices operating together to transport a medium. Assisted transport may be available and indeed required when, for example, one or more of the devices in the media path has a non-releasable drive mechanism, requiring the drive mechanisms of the two devices to operate together to transport the medium.
Referring now to the operation illustrated in
FIG. 3
, the operation begins when the leading edge
192
of the medium
190
reaches a predetermined handoff point
299
of the first media handling device
110
. When the controller
115
of the first media handling device
110
determines that the leading edge
192
of the medium
190
has reached the handoff point
299
, the controller
115
transmits a “MEDIA AT HANDOFF” signal
310
to the controller
125
of the second media handling device
120
. When the second media handling device
120
is ready for the medium
190
to be fed to its entry drive mechanism
122
, it transmits a “READY TO ACCEPT” signal
320
to the controller
115
of the first media handling device
110
. The controller
115
then causes the exit rollers or other drive mechanism
112
to transport the medium
190
toward the second media handling device
120
and transmits a “READY TO RELEASE” signal
330
to the controller
125
of the second media handling device
120
. Upon receiving the “READY TO RELEASE” signal
330
from the controller
115
, the controller
125
may then cause the entry rollers
122
of the second media handling device
120
to begin moving in preparation for receiving the medium
190
.
In one embodiment of an indexed-feed assisted operation, the controller
115
causes the medium
190
to be transported a predetermined length and then stopping, awaiting further instructions from the controller
125
of the second media handling device
120
. Before the medium
190
reaches the entry rollers
122
of the second media handling device, the controller
125
may transmit a “MOVE” signal
340
to other devices such as the first media handling device
110
. In response to the “MOVE” signal
340
, the controller
115
of the first media handling device
110
causes the exit rollers
112
to move and then issues a “MOVE DONE” signal
350
to the controller
125
, signaling a completion of that particular movement of the exit rollers
112
.
The speed and distance of the movement associated with each “MOVE” signal
340
may be pre-determined or negotiated between the two media handling devices
110
,
120
. The controller
125
of the second media handling device
120
may issue additional “MOVE” signals as needed for processing of the medium
190
. The additional “MOVE” signals may be issued before a “MOVE DONE” signal corresponding to the previous “MOVE” signal is received from the controller
115
of the first media handling device
110
.
When the controller
125
determines that the medium
190
has been received by the drive mechanism
122
of the second media handling device
120
, it transmits a “MEDIA ACCEPTED” signal
360
to the controller
115
of the first media handling device
110
.
While the medium is under control of the drive mechanisms
112
and
122
, e.g., both between the entry rollers
122
of the second media handling device
120
and between the exit rollers
112
of the first media handling device, a series of “MOVE” signals
370
may be transmitted by the controller
125
to the first media handling device
110
, with corresponding movement of the entry rollers
122
. In response to the “MOVE” signals
370
, the controller
115
of the first media handling device
110
causes the exit rollers
112
to move and then to issue a “MOVE DONE” signal
350
to the controller
125
, signaling a completion of that particular movement of the exit rollers
112
. Thus, the movement of the medium
190
may, at least partially through the second media handling device
120
, be assisted by the first media handling device
110
.
Each “MOVE” signal may be associated with a movement of the media necessitated by, for example, a print engine of the second media handling device
120
. The “MOVE” signal may cause the drive mechanisms
112
,
122
to move the medium
190
substantially in unison. Alternatively, the “MOVE” signal may cause the intentional creation of a slight buckle in the medium
190
. The buckle is created by the drive mechanism
112
of the first media handling device
110
moving the medium
190
prior to movement of the medium
190
by the drive mechanism
122
of the second media handling device
120
. The buckle ensures that the medium
190
will be available for movement when the second media handling device
120
is ready to process the medium
190
.
When the medium
190
has been transported out of the control of the first media handling device
110
(e.g., out of the exit rollers
112
), the controller
115
transmits a “MEDIA RELEASED” signal
390
to the controller
125
of the second media handling device
120
.
FIG. 4
illustrates the operation of a media handling system similar to that illustrated in
FIG. 1
using continuous feed in an assisted operation. Prior to the handoff operation, the first media handling device
110
transports the medium
190
through the device
110
. When the leading edge
192
of the medium
190
reaches the handoff point
299
, the movement of the medium
190
may be halted, and the controller
115
of the first media handling device
110
transmits a “MEDIA AT HANDOFF” signal
410
to the controller
125
of the second media handling device
120
. When the second media handling device
120
is ready for the medium
190
to be fed to its entry rollers
122
, it transmits a “MOVE” signal
420
to the controller
115
of the first media handling device
110
. The controller
115
then causes the exit rollers
112
to transport the medium
190
toward the second media handling device
120
until the medium
190
has exited the exit rollers
112
of the first media handling device
110
.
The second media handling device
120
may transmit the “MOVE” signal
420
prior to receiving the “MEDIA AT HANDOFF” signal
410
from the first media handling device
110
. In that instance, the first media handling device
110
will not halt the transportation of the medium
190
but may, nevertheless, transmit the “MEDIA AT HANDOFF” signal
410
when the leading edge
192
reaches the handoff point
299
.
When the second media handling device
120
receives the medium
190
between the entry rollers
122
, the controller
125
may transmit a “MEDIA ACCEPTED” signal
430
to the controller
115
of the first media handling device
110
. This signal, however, may be for information only, as the first media handling device
110
, in one embodiment, need not take any action based on the signal.
When the trailing edge
194
of the medium has advanced beyond the drive mechanism, e.g., the exit rollers
112
of the first media handling device
110
, the controller
115
transmits a “MEDIA RELEASED” signal to the controller
125
of the second media handling device
120
.
The type of handoff between two particular devices may be previously negotiated between the controllers of the two devices. For example, when the devices are initially installed in the media path or are connected via the communication link, the controllers may negotiate that the handoff will be performed using an assisted operation for an indexed feed. Thus, during subsequent handoffs, the upstream device will await certain signals from the downstream device and will respond accordingly. Similarly, the movement speed of the medium during the handoff may be negotiated. Certain signals such as the “PAGE ANNOUNCE”, “READY TO ACCEPT”, or “MOVE” signals may be accompanied with parameters providing the other devices desired values for those parameters. Such parameters may include the movement speed of the medium during handoffs.
In other embodiments, the negotiation of the handoff may take the form of a hierarchical system that designates a master and a slave according to the requirements of the devices. For example, if one of the devices in the handoff requires assisted operation while the other does not, the device requiring assisted operation may be designated as a master. The master device then supplies the necessary parameters for the handoff to the slave device. As a further example, if one device is a print engine and the other is a media input/output device, the print engine may be declared as the master. In another embodiment, the downstream device may always be designated as the master while the upstream device is the slave.
In other embodiments, the media path may include a series of media processing devices. For example, as illustrated in
FIG. 5
, three such devices may be placed in a series, forming a media path. An input machine
510
, a processing machine
520
and an output machine
530
each have a controller
515
,
525
,
535
. The controllers are linked by a communication link
550
. The input machine
510
has an exit drive mechanism
512
, and the output machine
530
has an entry drive mechanism
532
. The intermediate processing machine
520
is shown with a plurality of drive mechanisms including entry drive mechanism
522
, intermediate drive mechanism
524
, and exit drive mechanism
526
.
The handoff of a medium from the input machine
510
to the processing machine
520
, and the handoff from the processing machine
520
to the output machine
530
, may be performed similarly to the handoffs described above with reference to
FIGS. 2-4
.
Thus, a media handoff protocol according to the present invention allows handoff of a medium between two media handling devices under the control of separate controllers for either continuous or indexed feed. Additionally, a system according to the invention may accommodate either assisted or unassisted transport of the medium.
While particular embodiments of the present invention have been disclosed, it is to be understood that various different modifications and combinations are possible and are contemplated within the true spirit and scope of the appended claims. There is no intention, therefore, of limitations to the exact abstract or disclosure herein presented.
Claims
- 1. A method of media handoff from a first device to a second device, comprising:transmitting a first signal from said first device indicating a medium at a predetermined handoff point; receiving a second signal from said second device instructing said first device to transport said medium toward said second device; transporting said medium toward said second device; receiving a third signal from said second device indicating acceptance of said medium by said second device; receiving a fourth signal from said second device instructing said first device to transport said medium a predetermined distance; and transporting the medium said predetermined distance.
- 2. A method according to claim 1, further comprising:releasing said medium from said first device before said medium has exited said first device.
- 3. A method according to claim 1, further comprising:transmitting a fifth signal from said first device upon completion of said transporting the medium said predetermined distance.
- 4. A method according to claim 1, further comprising:designating one of said first device and said second device as a master device and another of said first device and said second device as a slave device, said master device transmitting instructions to said slave device.
- 5. A method according to claim 4, wherein said designating designates according to a hierarchy.
- 6. A method of media handoff from a first device to a second device, comprising:receiving a first signal from said first device indicating a medium at a predetermined handoff point; transmitting a second signal from said second device instructing said first device to transport said medium to said second device; transmitting a third signal from said second device indicating acceptance of said medium by said second device; and transmitting a fourth signal from said second device instructing said first device to transport the medium a predetermined distance.
- 7. A method according to claim 6, further comprising:receiving a fifth signal from said first device upon transporting of the medium said predetermined distance by said first device.
- 8. A method according to claim 6, further comprising:designating one of said first device and said second device as a master device and another of said first device and said second device as a slave device, said master device transmitting instructions to said slave device.
- 9. A method according to claim 8, wherein said designating designates according to a hierarchy.
- 10. A media handoff system, comprising:a first media handling device comprising: a first media driver for transporting a medium through said first media handling device; and a first controller for controlling said first media driver; and a second media handling device comprising: a second media driver for receiving the medium from said first media handling device and transporting said medium through said second media handling device; and a second controller for controlling said second media driver and being adapted to communicate with said first controller; wherein said first controller is designed to receive signals from said second controller and to start or stop said first media driver while said medium is being transported through said second media handling device in response to said signals.
- 11. The media handoff system according to claim 10, wherein at least one of said first media handling device and said second media handling device is a printer.
- 12. The media handoff system according to claim 10, wherein at least one of said first media driver and said second media driver is a set of rollers.
- 13. The media handoff system according to claim 10, wherein said medium is a sheet of paper.
- 14. A program product, comprising machine readable program code for causing a machine to perform following method steps:transmitting a first signal from a first device indicating a medium at a predetermined handoff point; receiving a second signal from a second device instructing said first device to transport said medium toward said second device; transporting said medium toward said second device; receiving a third signal from said second device indicating acceptance of said medium by said second device; receiving a fourth signal from said second device instructing said first device to transport the medium a predetermined distance; and transporting the medium said predetermined distance.
- 15. The program product according to claim 14, wherein said program code causes a machine to further perform the following method step:transmitting a fifth signal from said first device upon completion of said transporting the medium said predetermined distance.
- 16. A program product, comprising machine readable program code for causing a machine to perform following method steps:receiving a first signal from a first device indicating a medium at a predetermined handoff point; transmitting a second signal from a second device instructing said first device to transport said medium to said second device; transmitting a third signal from said second device indicating acceptance of said medium by said second device; and transmitting a fourth signal from said second device instructing said first device to transport the medium a predetermined distance.
- 17. The program product according to claim 16, wherein said program code causes a machine to further perform the following method step:receiving a fifth signal from said first device upon transporting of the medium said predetermined distance by said first device.
US Referenced Citations (9)