U.S. patent application number 11/155802 was filed with the patent office on 2007-01-04 for media feeding management.
This patent application is currently assigned to Lexmark International, Inc.. Invention is credited to Douglas Anthony Able, Kevin Dean Schoedinger, James Christopher Woods.
Application Number | 20070001388 11/155802 |
Document ID | / |
Family ID | 37588509 |
Filed Date | 2007-01-04 |
United States Patent
Application |
20070001388 |
Kind Code |
A1 |
Able; Douglas Anthony ; et
al. |
January 4, 2007 |
Media feeding management
Abstract
The present invention relates to an apparatus, system and method
for managing media throughput in a printing device that may
incorporate a sensing device. The gaps between feeding successive
sheets of media may be controlled. The printing device may operate
using different feeding modes having different gaps between the
sheets of media.
Inventors: |
Able; Douglas Anthony;
(Shelbyville, KY) ; Schoedinger; Kevin Dean;
(Lexington, KY) ; Woods; James Christopher;
(Midway, KY) |
Correspondence
Address: |
LEXMARK INTERNATIONAL, INC.;INTELLECTUAL PROPERTY LAW DEPARTMENT
740 WEST NEW CIRCLE ROAD
BLDG. 082-1
LEXINGTON
KY
40550-0999
US
|
Assignee: |
Lexmark International, Inc.
|
Family ID: |
37588509 |
Appl. No.: |
11/155802 |
Filed: |
June 17, 2005 |
Current U.S.
Class: |
271/258.01 |
Current CPC
Class: |
B65H 2701/1313 20130101;
B65H 7/08 20130101; B65H 2511/22 20130101; B65H 2701/1311 20130101;
B65H 2513/514 20130101; B65H 2511/11 20130101; B65H 2220/02
20130101; B65H 2220/02 20130101; B65H 2220/01 20130101; B65H
2220/03 20130101; B65H 2220/03 20130101; B65H 2220/01 20130101;
B65H 2511/514 20130101; B65H 2701/1313 20130101; B65H 2301/4452
20130101; B65H 2511/414 20130101; B65H 2701/1311 20130101; B65H
2511/414 20130101; B65H 2513/514 20130101; B65H 2511/11 20130101;
B65H 2513/511 20130101; B65H 2513/511 20130101 |
Class at
Publication: |
271/258.01 |
International
Class: |
B65H 7/02 20060101
B65H007/02 |
Claims
1. A method to control a gap between feeding of sheets of media in
a printing device including a sensor, wherein said printing device
is capable of feeding according to either a first mode or a second
mode, the first mode comprising selecting a first gap based upon a
measured page length time (PL.sub.m) for a sheet of media; the
second mode comprising feeding successive sheets of media with a
second gap that is different from said first gap.
2. The method of claim 1 wherein said first mode further comprises:
providing said sensor to detect a leading and trailing edge of
media passing said sensor; identifying a page length time
(PL.sub.m) for a sheet of media based on said leading and trailing
edge of media passing said sensor; measuring a page length time
(PL.sub.m) for one or more page lengths to pass said sensor; and
selecting said gap during feeding subsequent sheets of media based
upon said measured page length time (PL.sub.m).
3. The method of claim 1 wherein second mode further comprises:
identifying a trailing edge of a sheet of media passing said
sensor; and feeding a subsequent sheet of media when said trailing
edge is identified.
4. The method of claim 2 wherein said gap comprises a gap time
interval which comprises the time between detection of a trailing
edge of sheet of media and a leading edge of a subsequent sheet of
media.
5. The method of claim 1 wherein said device is capable of changing
from feeding in said first mode to said second mode based upon
information received from said sensor.
6. The method of claim 1 wherein said device is capable of changing
from said first mode to said second mode when said sensor fails to
detect a trailing edge of media after a selected period of
time.
7. The method of claim 6 wherein said selected period of time
exceeds the PL.sub.m of a prior sheet of media.
8. The method of claim 1 wherein said device is capable of changing
from feeding in said first mode to said second mode based upon user
input.
9. The method of claim 1 wherein said printing device includes a
processor and said processor is capable of changing from feeding in
said first mode to said second mode.
10. The method of claim 9 wherein said processor initiates said
second feeding mode when said user identifies a type of media to
said processor.
11. The method of claim 9 wherein said processor initiates said
second feeding mode when said user identifies a particular feed
source.
12. The method of claim 1 wherein said sensor fails to detect a gap
between successive sheets of media n and n+1 and said device is
capable of printing information scheduled for sheet n+1 on sheet
n+2.
13. A media feeding apparatus comprising: a sensor and a processor
in communication with said sensor wherein said processor is
configured to feed according to either a first mode or a second
mode, wherein said processor is configured in said first mode to
select a first gap based upon a measured page length time
(PL.sub.m) for a sheet of media; wherein said processor is
configured in said second mode to select a second gap that is
different than said first gap.
14. The media feeding apparatus of claim 13 wherein said sensor is
capable of detecting a leading and trailing edge of media passing
said sensor; and said processor in said first feeding mode is
further configured to identify a measured page length time
(PL.sub.m) for a sheet of media and select said gap during feeding
between subsequent sheets of media based upon said measured page
length time (PL.sub.m).
15. The media feeding apparatus of claim 13 wherein said processor
in said second mode is further configured to: identify a trailing
edge of a sheet of media passing said sensor; and feed a subsequent
sheet of media when said trailing edge is identified.
16. The media feeding apparatus of claim 13 wherein said processor
is configured to change from feeding in said first mode to said
second mode based upon information received from said sensor.
17. The media feeding apparatus of claim 13 wherein said processor
is configured to change from said first mode to said second mode
when said sensor fails to detect a trailing edge of media after a
selected period of time.
18. The media feeding apparatus of claim 17 wherein said selected
period of time exceeds the PL.sub.m of a prior sheet of media.
19. The media feeding apparatus of claim 13 wherein said processor
is configured to change from feeding in said first mode to said
second mode based upon user input.
20. The media feeding apparatus of claim 13 wherein said processor
is configured to change from feeding in said first mode to said
second mode when said user identifies a type of media to said
processor.
21. The media feeding apparatus of claim 20 wherein said processor
is configured to change from feeding in said first mode to said
second mode when said user identifies a particular feed source.
22. The media feeding apparatus of claim 13 wherein said sensor
fails to detect a gap between successive sheets of media n and n+1
and said device is configured to print information scheduled for
sheet n+1 on sheet n+2.
23. An article comprising: a storage medium having stored thereon
instructions when executed by a machine result in the following
operations: feeding according to one of: a first feeding mode
comprising selecting a first gap based upon a measured page length
time (PL.sub.m) for a sheet of media; a second feeding mode
comprising feeding successive sheets of media with a second gap
that is different from said first gap.
24. The article of claim 23 wherein said instructions when executed
by said machine result in the following additional operations when
feeding in said first mode: identifying a page length time
(PL.sub.m) for a sheet of media based on said leading and trailing
edge of media passing a sensor; measuring a page length time
(PL.sub.m) for one or more page lengths to pass said sensor; and
selecting said gap during feeding subsequent sheets of media based
upon said measured page length time (PL.sub.m).
25. The article of claim 23 wherein said instructions when executed
by said machine result in the following operations when feeding in
said second feeding mode: identifying a trailing edge of a sheet of
media passing a sensor; and feeding a subsequent sheet of media
when said trailing edge is identified.
26. The article of claim 23 wherein said instructions when executed
by said machine result in the following operations: changing from
feeding in said first mode to said second mode based upon
information received from said sensor.
27. The article of claim 23 wherein said instructions when executed
by said machine result in the following operations: changing from
said first mode to said second mode when said sensor fails to
detect a trailing edge of media after a selected period of
time.
28. The article of claim 27 wherein said instructions when executed
by said machine result in the following: said selected period of
time exceeds the PL.sub.m of a prior sheet of media.
29. The article of claim 23 wherein said instructions that when
executed by said machine result in the following operations:
changing from feeding in said first mode to said second mode based
upon user input.
30. The article of claim 23 wherein said instructions when executed
by said machine result in the following operations: changing from
feeding in said first mode to said second mode wherein said second
feeding mode is initiated by a user identifying a type of
media.
31. The article of claim 23 wherein said instructions when executed
by said machine result in the following operations: changing from
feeding in said first mode to said second mode wherein said second
mode is initiated by a user identifying a particular feed
source.
32. The article of claim 23 wherein said instructions when executed
by said machine result in the following operations: printing
information scheduled for sheet n+1 on sheet n+2 when a gap is not
detected between successive sheets of media n and n+1 after a
selected period of time.
33. A media feeding apparatus comprising: a sensor and a processor
in communication with said sensor wherein said processor is
configured to feed according to a first mode or a second mode,
wherein said processor is configured in said first mode to select a
first gap based upon a measured feed time (FTm) for a sheet of
media; wherein said processor is configured in said second mode to
select a second gap that is different from said first gap.
34. The media feeding apparatus of claim 33 wherein said sensor is
capable of detecting a leading and trailing edge of media passing
said sensor; and said processor in said first feeding mode is
further configured to communicate with said sensor and configured
to identify a measured feed time (FT.sub.m) for a sheet of media
and select said gap for a subsequent sheet of media based upon said
measured feed time (FT.sub.m).
35. The media feeding apparatus of claim 33 wherein said processor
in said second mode is further configured to: identify of a
trailing edge of a sheet of media passing said sensor; and feed a
subsequent sheet of media when said trailing edge is
identified.
36. The media feeding apparatus of claim 33 wherein said sensor
fails to detect a gap between successive sheets of media n and n+1
and said device is configured to print information scheduled for
sheet n+1 on sheet n+2.
Description
FIELD OF INVENTION
[0001] The present invention relates to an apparatus, system and
method for managing media feeding in printing devices.
BACKGROUND
[0002] Faster feeding of sheets of media from a stack of sheets
will increase the throughput of a printer. Therefore, it is desired
to maximize the throughput of a printer by feeding sheets from the
stack of sheets at the fastest rate possible. When feeding sheets
from a stack of sheets to a processing station in a printing
device, it may be desired to feed the sheets as quickly as possible
without a paper jam. To prevent a paper jam it may be useful to
prevent the sheets from overlapping. Thus a minimum gap may be
maintained between adjacent sheets being fed to prevent the sheets
from overlapping while maintaining a desired feed rate.
[0003] There are times, however, when paper may jam in the printer
for various reasons such as slippage of the feed rollers on the
media. The slippage may be caused, for example, by use of media
with a smoother surface than anticipated. The slippage may cause
multiple sheets to stop in the paper path. The user may then need
to clear the paper path with risk of damage to the printer or risk
pieces of the media remaining in delicate areas of the printer,
which may cause future failures.
SUMMARY
[0004] The present invention relates to a method or apparatus that
may control a gap time interval between feeding of sheets of media
in a printing device that may include a sensor and feeding
according to a first feeding mode. The first feeding mode may
comprise measuring a page length time (PL.sub.m) for one or more
page lengths to pass the sensor. The gap time period may also be
controlled during feeding sheets of media based upon the measured
page length time. The first feeding mode may also comprise
measuring a feed time (FTm) for one or more pages passing the
sensor. The gap period may also be controlled during feeding sheets
of media based upon the measured feed time. The method or apparatus
may also include a second feeding mode. The second feeding mode may
delay feeding a subsequent sheet of media until a prior sheet of
media clears the sensor. The method or apparatus may also adapt and
change between the first and second feeding modes.
BRIEF DESCRIPTION OF DRAWINGS
[0005] Features and advantages of the present invention are set
forth herein by description of embodiments consistent with the
present invention, which description should be considered in
conjunction with the accompanying drawings, wherein:
[0006] FIG. 1 is a side view of an exemplary embodiment of a
printing device illustrating an electrophotographic device.
[0007] FIG. 2 is a top view of an exemplary embodiment of a media
feed tray.
[0008] FIG. 3 is a side view of an exemplary embodiment of a media
feed tray.
[0009] FIG. 4 is an exemplary embodiment of a timing diagram
relating to sensor state.
[0010] FIG. 5 is an exemplary embodiment of a timing diagram
relating to gap and pick delay.
[0011] FIG. 6 is an exemplary embodiment of the present invention
illustrating a method for "page length" mode.
[0012] FIG. 7 is an exemplary embodiment of the present invention
illustrating a method for "feed time" mode.
[0013] FIG. 8 is an exemplary embodiment of the present invention
illustrating a method for "consistent" mode.
[0014] FIGS. 9 and 10 are an exemplary embodiment of the present
invention illustrating adaptation.
[0015] FIGS. 11 and 12 are an exemplary embodiment of the present
invention illustrating another form of adaptation.
[0016] FIG. 13 is an illustration of an embodiment of the present
invention relating to an article of machine readable media in
relation to a processor and a user interface.
DETAILED DESCRIPTION
[0017] The present invention relates to the management of feeding
media in a printing device. A printing device may be any device
which creates images, such as text, characters or graphics, on
media. Accordingly, a printing device may be an inkjet printer, an
electrophotographic printer, a copier, a fax, an all-in-one device,
or a multifunctional device.
[0018] An exemplary embodiment of a printing device may be an
electrophotographic printer, illustrated in FIG. 1. Accordingly,
the following describes an electrophotographic printer that may be
suitable for use in the present invention.
[0019] The optical device 1 may project a light image onto a
photosensitive drum 7 by projecting light on the basis of image
information read from an external apparatus or the like. As shown
in FIG. 1, a laser diode 1b, a polygon mirror 1c, a scanner motor
1d, and an image-forming lens 1e may be housed inside an optical
unit 1 of the main body 14 of the apparatus. When, for example, an
image signal may be supplied from an external apparatus, such as a
computer, word processor or imaging device, to the printer or to a
microprocessor 16 within the printer, the laser diode 1b may emit
light in response to the image signal, and projects the light onto
the polygon mirror 1c as image light. Polygon mirror 1c may be
rotated at high speed by the scanner motor 1d. The image light
reflected by the polygon mirror 1c may be projected onto the
photosensitive drum 7 via the image-forming lens 1e and reflecting
mirror 1f. The surface of the photosensitive drum 7 may thus be
selectively exposed to form a latent image corresponding to the
image information.
[0020] The feeding device 3 for feeding the recording medium 2
(e.g., recording paper, cardstock, OHP sheet, envelopes, cloth,
thin plate, etc.) may include the following components. A loading
portion of a cassette 3a may be provided in the inner bottom
portion of the main body 14 of the apparatus. Upon the input of an
image formation start signal, the recording media 2 within the
cassette 3a may be fed one-by-one from the top of the stack by a
pickup roller 3b, feeding rollers 3c and follower rollers 3d,
pressed against the feeding roller 3c.
[0021] A sheet of recording medium 2 may be fed to the nip portion
between the photosensitive drum 7 and the transfer device 4 in
synchronization with the performing of the image-formation
operation described above, transferring the image to the recording
medium. The recording medium 2 onto which a developed image has
been transferred may be fed to the fixing device 5 and then ejected
onto the ejection tray 6 by a pair of intermediate ejection rollers
3e and a pair of ejection rollers 3f. A pair of guide members 3g
for guiding the feeding of the recording medium 2 may be provided
between each of the above-mentioned pairs of rollers.
[0022] The transfer device 4 transfers the developed latent image
or toner image formed on the photosensitive drum 7 in the
image-forming section onto the recording medium 2. The transfer
device 4 consists of the transfer roller 4 as shown in FIG. 1. That
is, the recording medium 2 may be pressed by the transfer roller 4
against the photosensitive drum 7 of the loaded process cartridge
B. A voltage having a polarity opposite that of the latent image
formed on the photosensitive drum 7 may be applied to the transfer
roller 4 so that the developing agent on the photosensitive drum 7
may be transferred to the recording medium 2.
[0023] The fixing device 5 may fix the developing agent image
transferred to the recording medium 2 by applying heat and pressure
to the recording medium 2 carrying the toner image. As shown in
FIG. 1, the fixing device 5 may comprise a driving rotating roller
5a having a heater 5b therein, and a fixing (pressure) roller 5c,
rotating in a driven manner in pressed contact with the drive
roller 5a. More specifically, when the recording medium 2 to which
the developing agent image has been transferred moves between drive
roller 5a and fixing roller 5c, heat may be applied by the heater
located in the driving rotating roller 5a and pressure may be
applied to the recording medium by the fixing roller 5c, thereby
causing the developing agent (which comprises a colorant and a
thermoplastic component) on the recording medium 2 to melt and
become fixed to the recording medium 2.
[0024] Furthermore, the microprocessor 16 may communicate with a
computer, network, word processor or imaging device using a variety
of communication protocols. The microprocessor 16 may also process
data within the printer, including data related to sensors and
computing algorithms.
[0025] A process cartridge loading device by which the process
cartridge B may be loaded into the image forming apparatus may be
disposed within the apparatus A. Loading and unloading of the
process cartridge B to and from the main body 14 of the apparatus
may be performed by opening an open/close cover 15. Open/Close
cover 15 may be provided with a conventional hinge (not shown) so
that it can be opened or closed, and is mounted in the upper
portion of the main body 14 of the apparatus. Opening the
open/close cover 15 may reveal a cartridge loading space provided
inside the main body 14 of the apparatus and may include
conventional left and right guide members (not shown) mounted on
the left and right inner-wall surfaces of the main body 14. Each of
these guide members may be provided with a guide for inserting the
process cartridge or developing agent assembly B. The process
cartridge or assembly B may be inserted into and along the guides,
and by closing the open/close cover 15. Furthermore, the open/close
cover 15 may be provided in communication with a sensor (not
illustrated), which may be triggered by opening or closing said
cover 15.
[0026] The process cartridge or assembly B may comprise an image
carrier and at least one process means. The process device may
include a charging device for charging the surface of the image
carrier, a developing device for forming a toner image on the image
carrier, a cleaning device for cleaning the toner remaining on the
surface of the image carrier, and the like. In the process
cartridge B as shown is the charging device 8, the exposure section
9, the developing device 10, and the cleaning device 11 may be
arranged around a photosensitive drum 7, which is an image carrier.
These elements may be housed within a frame member formed of the
developing agent frame member 12 and the cleaning frame member 13
so that they may be formed into one unit, thus making it possible
to load and unload the unit into and out of the main body 14 of the
apparatus. The process cartridge B may include the following
elements: the photosensitive drum 7, the charging device 8, the
exposure section 9, the developing device 10 and the cleaning
device 11. However, it should be appreciated that some of these
devices, such as the charging device 8, may be otherwise arranged
within the main body 14 of the printing device.
[0027] The photosensitive drum 7 may have an organic photosensitive
layer coated onto the outer peripheral surface of a cylindrical
drum base formed from aluminum. The photosensitive drum 7 may be
rotatably mounted on a frame member of the cartridge and the
driving force of a drive motor disposed in the main body 14 of the
apparatus may be transmitted to a drum cap (not shown). As a
result, the photosensitive drum 7 may be caused to rotate in the
direction of the arrow.
[0028] The charging means 8 may be used to uniformly charge the
surface of the photosensitive drum 7. Preferably, a so-called
contact charging method in which the charging means 8 is mounted on
frame member 12 may be used.
[0029] The charging means 8 may be brought into contact with the
photosensitive drum 7 so that the charging means 8 contacts the
photosensitive drum 7 during the image formation. A DC voltage may
be applied to the charging means 8 and the surface of the
photosensitive drum 7 may be uniformly charged.
[0030] An exposure section 9 exposes a light image projected from
the optical means onto the surface of the photosensitive drum 7
uniformly charged by the charging roller 8 so that a latent image
may be formed on the surface of the photosensitive drum 7. An
opening 9 for guiding the light image onto the top surface of the
photosensitive drum 7 may be provided to form the exposure
section.
[0031] FIG. 2 illustrates a sheet support tray of the present
invention that may contain a stack of sheets therein for
advancement by a pick mechanism. A tray 210, which may be located
inside of a printer 211, for example, may be used to support sheets
of media, such as, but not limited to, paper, card stock, film,
such as transparencies, or printer labels, in a stack.
[0032] At the front end 216 of the tray 210, there may be an
inclined wall 217, inclined at an obtuse angle from a bottom wall
215. On the inclined wall 217 may be a number of ribs 218 on which
the sheet stack may be engaged. A pick mechanism 220 may be used to
advance the media from the tray 210. The pick mechanism 220 may
include a pair of feed rollers 221 and 222, which are driven from a
motor 223 through a gear train, (not illustrated).
[0033] Referring to FIG. 3, the motor 323 may be alternately turned
off and on by a processor 324 as each of the sheets 312 may be
advanced from the top of the stack 314 of the sheets. A sheet 312
may be advanced along the inclined wall 317 through a predetermined
feed path 319 and into a processing station, (not illustrated,) of
the printer 311 where the media is printed. Located along the media
feed path 319 may be a sensor 325, which may be in communication
with the microprocessor 324.
[0034] In order to feed the sheets properly, a gap G may be
maintained between consecutive sheets, for example sheet n and
sheet n+1, to prevent the sheets from jamming or feeding multiple
sheets at the same time. The gap G may be the distance between the
trailing edge of sheet n and the leading edge of sheet n+1.
However, it may be advantageous to keep this gap as small as
possible to minimize the amount of time required between feeding
individual sheets and to maintain a desired throughput.
[0035] Accordingly, the present invention is directed to an
apparatus, system and method that may provide a gap between the
sheets of media 312 that may utilize a media detection or input
sensor 325 located along the media feed path 319 within the
printing device, illustrated in FIG. 3. When media 312 is fed and
passes by the sensor 325, the sensor 325 may be activated. It
should be appreciated that the sensor may be any device, such as
proximity or optical device, which may be capable of detecting a
sheet of media.
[0036] Illustrated in FIG. 4 is a timing diagram of an exemplary
embodiment of the state of the sensor as media travels through the
printer. When the media is picked, 410, the sensor may be in an
inactive or deactivated state. The sensor may remain deactivated,
for example, while the media is traveling to the sensor, 420. When
the leading edge of the media passes the sensor, the sensor may be
activated 430. The sensor may remain activated during the amount of
time necessary for the trailing edge of the media to pass the
sensor 440. Once the trailing edge of the media passes by the
sensor, the sensor may be deactivated at 450.
[0037] In one embodiment of the present invention, a determination
of the length of the sheet of media (PL.sub.m) may be made by the
printing device. This determination may be utilized when the length
of a sheet of media (PL) is unknown, such as when media is fed from
a multipurpose tray, when the printing device lacks the ability to
sense the length of a sheet of media or when the user uses a
different sized sheet of media than what is programmed into the
printing device. By determining the length of the sheet of media,
the time between feeding sheets may be controlled to maintain an
appropriate gap between the pages and speed the media feeding
process to obtained desired throughput times. This mode of
operation may be referred to herein as the "page length" mode. The
"page length" mode may therefore be accomplished by the following
methodology.
[0038] When the sensor is activated, a signal may be sent to the
microprocessor representing the amount of time necessary for the
media to pass by the sensor. From a combination of this time
period, illustrated in FIG. 4 at 440, and other known factors, such
as the velocity at which the media travels, which may be determined
by the motor speed, etc., a determination may be made defining the
length of the sheet of media. The measured length of the sheet of
media may then be used to determine how to pick subsequent sheets
and to maintain a desired gap.
[0039] In an embodiment of the invention, illustrated in FIG. 5, it
is first useful to point out that the time necessary to feed a full
sheet length (PL.sub.m) from the tray and maintain a desired gap
(G) may be determined by measuring the time between the
microprocessor (not illustrated) sending a pick signal to begin the
sheet feeding process and the microprocessor receiving a signal
from a sensor 525 that detects the leading edge of the sheet 530.
It can be appreciated that the time necessary to feed a full sheet
and maintain a gap may be based upon the distance of the
predetermined media path 319 (see FIG. 3) and other constants (e.g.
velocity).
[0040] The expected feed time (FT.sub.exp) may be considered the
amount of time necessary for the leading edge 530 of a sheet n to
trigger sensor 525 after the picking process has been initiated by
the pick signal. The pick delay (PD) may be considered the amount
of time lapsed after the expected feed time (FT.sub.exp) and prior
to picking of the next sheet, sheet n+1. This relationship may be
represented by the following equation: PD+FT.sub.exp=PL.sub.m+G.
Thus, solving for PD, the pick delay may be determined by the
following equation: PD=PL.sub.m+G-FT.sub.exp.
[0041] An exemplary method for adjusting the gap according to media
length is illustrated in FIG. 6. The printer may be turned on, or
started from standby mode or power save mode, at 610. At 612, a
print job may be generated. A determination may be made on whether
a print job may be a multiple page print job at 614. If the print
job is not a multiple page print job the page may be printed
616.
[0042] If the print job is a multiple page print job then sheet n
is picked 618. When the leading edge of sheet n passes by the input
sensor, the input sensor may be activated 620 and sends a signal to
the microprocessor which starts a timing device such as internal
clock (not illustrated) or maintains a pulse count, which may be
based on the clock time of the microprocessor or a specific period
of time chosen. Once the trailing edge of sheet n passes the input
sensor, the sensor may be deactivated 622 and the next sheet of
media, sheet n+1, may be picked at 624 and the input sensor may be
activated at 626.
[0043] Once the sensor has been deactivated for sheet n at 622, the
microprocessor, may then compute the length of the media (PL.sub.m)
from the amount of time necessary for the media to pass the sensor
and, for example, the speed at which the media may be traveling
determined from the pick motor. Using the relationships described
herein, a pick delay may be set based upon the measured media
length (PL.sub.m) and a desired gap.
[0044] Accordingly, in an exemplary embodiment, the feed time may
be measured for a sheet n. The expected feed time FT.sub.exp for
subsequent sheets, n+1, n+2, etc. may then be determined by the
measured feed time FT.sub.m for sheet n. The gap time G, may be a
desired gap length that may be translated into a time factor based
on the velocity of the paper moving through the printer. It should
be appreciated that the gap distance may be shorter than the
distance between the input sensor and the pick mechanism. Using
these factors it may then be possible to set a pick delay PD for
subsequent sheets which may be adjusted to control or minimize the
gap. A subsequent sheet, sheet n+2, may be picked at 628 according
to the selected pick delay.
[0045] When the trailing edge of sheet n+1 passes the sensor, the
sensor may be deactivated 630. The sensor may then be activated
again at 632 for sheet n+2. If sheet n+2 is the final sheet as
illustrated at 634, then the sensor may be de-activated at 636 and
process may end until another print job is generated at 612. If
sheet n+2 is not the last sheet then a subsequent sheet, sheet n+3
may be picked 638 according to the determined pick delay and the
sensor responds, at 630-632, until a final page is reached at
634.
[0046] It should be appreciated that once the pick delay is
identified which would allow one to control the gap time G, which
should be understood as either maintaining a constant gap time or
increasing the gap time or reducing the gap time, the
implementation of a desired pick delay can be applied at any point
in time. In addition, while the pick delay PD may be identified
after the first sheet of media is picked, it can also be
appreciated that the pick delay PD may be identified using any
sheet media that may be fed to the printer. In this manner the
system may allow the printer to control or minimize a gap depending
upon, e.g. the size of a print job.
[0047] In another embodiment the gap may be controlled or minimized
based on the measured feed time (FTm) of one or more sheets of
media, referred to herein as "feed time" mode. As alluded to above,
the feed time (FTm) of a sheet of media may be considered the
amount of time between when a pick signal is issued by the
processor and when the leading edge of a sheet of media reaches the
sensor, wherein the sensor may be activated. Accordingly, the
measured feed time (FI m) for a sheet n, may be used as the
expected feed time (FTexp) for a subsequent, such as sheet n+1.
[0048] Using the relationship PD=PL+G-FT.sub.exp an appropriate
pick delay (PD) may be calculated by supplying a page length (PL)
and desired gap (G) to the processor. The pick delay may be
optimized for either maintaining a consistent throughput of media
through the printing device or maintaining a consistent gap. This
page length may be a page length determined from tray settings
and/or user settings. The desired gap may be a set number for all
media or a number determined for media type. The desired gap may
also be set by the processor, or another device communicating with
the processor.
[0049] Additionally, a factor of time HB may be added to the feed
time expected to adjust the pick delay. This factor of time HB may
be a desired preset number or a processor pulse or multiple
processor pulses. For example, the factor of time may be any amount
of time between 1 millisecond to 50 milliseconds and any increment
therebetween, including 10 milliseconds, 11 milliseconds, 22
milliseconds, etc.
[0050] Furthermore, the measured feed time FTm may be compared to a
maximum feed time FTmax. The FTmax may be set at a desired maximum
feed time. For example, the maximum feed time may be the amount of
time it may take to feed the last sheet of media from a media stack
in a specific tray or it may be the amount of time necessary to
feed a page length (PL). Accordingly, if the measured feed time FTm
for sheet n+1 is greater than the maximum feed time FTmax then the
feed time expected for a subsequent sheet FTexp.sub.(n+2) may again
be set at the expected feed time for a previous sheet, such as
FTexp.sub.(n+1).
[0051] An exemplary embodiment of "feed time" mode is illustrated
in FIG. 7. At 710 the power may be turned on to the printing device
or the printing device may be in standby or power save mode. At 112
a print job may be generated. A pick signal may be issued at 714
and a determination may be made as to whether the sheet of media
being printed is a first sheet of media at 716.
[0052] If the sheet is a first sheet n, then the sensor may be
activated when the leading edge of the sheet reaches the sensor at
718 and the feed time may be measured FTm(n). The measured feed
time FTm.sub.(n) may be set as the expected feed time for the next
sheet of media FTexp.sub.(n+1) at 720. The value of the expected
feed time for the next sheet of media FTexp.sub.(n+1) may then be
used to calculate a pick delay (PD) according to the relationships
described herein at 740.
[0053] If it is determined that the sheet is not a first sheet n,
then the sensor may be deactivated by the trailing edge of a prior
sheet n at 722. The sensor may then be activated when the leading
edge of the sheet, sheet n+1, reaches the sensor at 724 and the
feed time may be measured FTm.sub.(n+1). A determination may then
be made as to whether the measured feed time for sheet n+1
FTm.sub.(n+1) may be greater than a maximum feed time FTmax at
726.
[0054] If the measured feed time for sheet n+1, FTm.sub.(n+1) is
greater than a maximum feed time FTmax at 726, then the feed time
expected for the next sheet sheet n+2, FTexp.sub.(n+2), may be set
to the feed time expected for a previous sheet, such as
FTexp.sub.(n+1), at 728. This value may then be used to calculate a
pick delay for the next sheet, sheet n+2 at 740. It should be
appreciated that the deactivation of the sensor between a pick
signal and the activation of the sensor may not affect the
measurement of the feed time. Furthermore, depending on the desired
gap, it should also be appreciated that the sensor may be
deactivated prior to the pick signal for a subsequent page being
activated.
[0055] If the measured feed time for sheet n+1, FTm.sub.(n+1) is
not greater than the maximum feed time FTmax, then a determination
may be made at 730 of whether the measured feed time for sheet n+1,
FTm.sub.(n+1) is less than the expected feed time for sheet n+1,
FTexp.sub.(n+1). If the feed time measured for sheet n+1,
FTm.sub.(n+1) is less than the expected feed time for sheet n+1,
FTexp.sub.(n+1) then the measured feed time FTm.sub.(n+1) may be
set as an expected feed time for the next sheet, sheet n+2,
FTexp.sub.(n+2) at 732. This value FTexp.sub.(n+2) may then be used
to determine the pick delay for the next sheet, sheet n+2 at
740.
[0056] If the measured feed time for sheet n+1, FTm.sub.(n+1) is
not less than the expected feed time for sheet n+1, FTexp.sub.(n+1)
at 730, then the feed time may be adjusted to pick the next sheet,
sheet n+2, sooner at 734 by adding a factor HB to the feed time.
Accordingly, the feed time expected for the next sheet, sheet n+2,
FTexp.sub.(n+2) may be the expected feed time for the sheet n+1,
FTexp.sub.(n+1) plus a factor HB, wherein
FTexp.sub.(n+2)=FTexp.sub.(n+1)+HB. The value of the expected feed
time for sheet n+2, FTexp.sub.(n+2) may then be used to determine
the pick delay for sheet n+2 at 740.
[0057] After a pick delay has been determined for the next sheet at
740, it may be determined whether there is another sheet to be
printed in the print job at 742. If there is another sheet to be
printed in the print job, the next sheet may be picked at 714. If
there is not another sheet to be printed, then the sensor may be
deactivated by the trailing edge of the sheet at 744 and the
printing device may wait for a new print job to be generated at
712.
[0058] It should be appreciated that the reference to a first sheet
n, is merely an arbitrary reference to the first sheet and the
above manipulation and setting of a pick delay may be initiated at
any point in a multi-page print job. For example, "feed time" mode
may be initiated at the first, fourth, twelfth or at any time or
sheet within a print job. Furthermore, as disclosed herein, it
should be understood that the reference to n, n+1, n+2, etc may
increase by one for each of the sheets being fed thereafter.
[0059] In an alternative embodiment of the present invention, it
may be necessary for the media to be fed in a manner that delays
feeding until a prior sheet clears the sensor before feeding the
subsequent sheet. Such embodiment may be used either alone or in
combination with the "page length mode" or "feed time mode"
discussed above. In such embodiment the printer may wait for a
sheet of media to clear the sensor prior to picking the next sheet.
This may provide improved gap management and may be invoked by the
user upon recognition of a feeding problem with difficult to handle
media (i.e., any media that may not properly or regularly engage
with a pick mechanism). Such feeding mode may therefore be
understood as an alternative feeding mode with a gap time that may
be different (e.g., longer) than that gap time in the "page length"
or "feed time" feeding modes.
[0060] Expanding upon the above, this alternative feeding mode may
therefore be triggered when the user identifies to the system a
media type that may be hard to feed. For example, any type of media
that may be difficult to pick and which may not be readily or
repeatedly engaged by feed roller 221 and 222 illustrated in FIG.
2. Accordingly, when the user identifies such information to the
processor, the processor may check against a preprogrammed table of
media, such as transparencies, labels, envelopes, glossy paper,
etc. and may instruct the system not to minimize the gap but to
maintain a relatively consistent or constant gap.
[0061] Alternatively, the user may themselves select a certain
input print setting that similarly does not seek to control or
minimize the gap. Furthermore, the printing device may select to
not seek to control or minimize the gap when a print job is sourced
from a particular feed source, such as a multi-purpose feed tray.
These various modes may be understood herein as a "consistent" feed
mode in the sense that the system may not seek to control or
minimize the gap and the gap may remain constant.
[0062] An exemplary embodiment of this second feeding mode may be
illustrated in FIG. 8. The printing device power may be turned on
or the printer may be activated from standby or power save mode at
810. Then a print job may be generated 812. A determination may
then be made as to whether the print job is a multi-page print job
at 814. If the print job is not a multi-page print job, the sheet
may be printed at 816.
[0063] If the print job is a multi-page print job a determination
may be made as to whether the user has selected the consistent feed
mode or if the printing device automatically set the consistent
feed mode at 818. If consistent feed mode has not been selected
then the printer may feed according another mode at 820, such as
the "page length" mode described above, measuring the length of the
first sheet of media as it passes through the printer, and
illustrated in FIG. 6, or the "feed time" mode illustrated in FIG.
7.
[0064] If consistent feed mode has been selected then the printing
device may pick the first sheet, sheet n, at 822. The input sensor
may be activated at 824 when the leading edge of the sheet has
passed the sensor. Once the trailing edge of the sheet has passed
the sensor, the sensor may be deactivated at 826. The printing
device may determine whether the page may be a final page at 828.
If the page is a final page, then the printing device may wait for
a new print job to be generated at 812. If the sheet is not the
final page in the print job, then the next sheet, sheet n+1, may be
picked at 830.
[0065] Accordingly, the subsequent sheet may not be picked until
the trailing edge of the prior sheet has passed the sensor. In this
manner the gap may not be controlled or minimized. While the pick
delay (PD) may or may not be identified in consistent mode, it
should be appreciated that the PD may (in the "consistent" mode)
relate to the following: PD=PL+FT.sub.exp.
[0066] Note that the page length may or may not be a measured page
length (PL.sub.m) as in this mode it may not be necessary to
measure the page length.
[0067] Furthermore, the printing device may adapt and switch
between the "page length" mode (see FIG. 6) or the "consistent"
mode (see FIG. 8). For example, when media feeding failures occur
due to gap closure, i.e. there is no gap between the sheets or
subsequent sheets have fed into the prior sheets, the printing
device may adjust between modes. One exemplary embodiment of the
adaptive method is illustrated in FIGS. 9 and 10.
[0068] In FIG. 9, the printing device may be turned on or activated
from standby or power save mode at 910. A print job may then be
generated at 912. It may then be determined whether the print job
is a multi-page print job at 914. If the print job is not a
multi-page print job then the page may be printed at 916.
[0069] When the print job is determined to be a multi-page print
job at 914, sheet n may be picked at 918. The sensor may be
activated by the leading edge of sheet n moving through the media
path at 920. Once the trailing edge of sheet n has passed the
sensor the sensor may be de-activated at 922 and the next sheet,
sheet n+1 may be picked at 924. Accordingly, it may now be possible
for an appropriate pick delay to be identified for a desired gap
length.
[0070] Sheet n+1 may activate the sensor at 926 and sheet n+2 may
be picked at 928 according to the calculated pick delay. At 930,
the trailing edge of sheet n+1 passes the sensor and the sensor may
be de-activated. Then the leading edge of sheet n+2 may pass the
sensor at 932. A determination may be made as to whether sheet n+2
may be the final sheet at 934. If it is the final sheet then as the
trailing edge of sheet n+2 passes the sensor, the sensor may be
deactivated at 936 and the printing device may wait for the next
print job at 912. If a determination is made that sheet n+2 may not
be the final sheet at 934, then sheet n+3 may be picked at 938.
[0071] In an exemplary embodiment of adaptation, a determination
may then be made as to whether the media sensor has been
de-activated at 940 for sheet n+2, which determination may be based
upon a selected period of time. It should be appreciated that the
selected amount of time may be greater than the time for a page
length to pass the sensor, PL. If the sensor has been de-activated
then the process may continue from 930. If the sensor has not been
de-activated, a possible feeding error may have occurred. For
example, it may indicate in this exemplary embodiment that sheet
n+3 may have been improperly fed and overlapped with sheet n+2. The
sensor may then detect a trailing edge of sheet n+3 which
improperly overlapped sheet n+2. At this point the system may
decide to adapt the process at 960 to consistent mode and elect to
print on sheet n+4 the print information that was intended for
sheet n+3. The system may elect not to adapt and proceed to step
940.
[0072] FIG. 10 illustrates an exemplary embodiment after adaptation
to consistent mode. At 1012, sheet n+4 may be picked, which may
replace any sheets not properly printed. The input sensor may be
activated by the leading edge of sheet n+3 at 1014. At 1016, the
trailing edge of sheet n+4 may pass the sensor and the sensor may
be de-activated. Then a determination may be made whether sheet n+4
is the final page in the print job at 1018, if so then the sensor
may be de-activated at 936 and the printing device may wait for a
new print job at 912 (illustrated on FIG. 9). If sheet n+4 is not
the final sheet a next sheet may be picked, sheet n+5, at 1020. The
process continues at until the final sheet has been picked.
Accordingly, the pick delay may not be controlled or minimized.
[0073] It should be appreciated that the decision to adapt may be
made at any time after sheet n+1 has been picked. Furthermore, it
should be appreciated that mode adaptation described herein may
occur after any given of number of undetected gaps, such as after
the second undetected gap has been determined, the fifth undetected
gap has been determined, the tenth undetected gap has been
determined, etc.
[0074] One non-limiting example of the above may be considered as
follows. One may send a four page print job to the printer. The
first page may be picked and fed through the printer. The second
page may be picked after the trailing edge of the first page may
clear the sensor. The third page may be picked based upon the gap
needed for fastest throughput ("page length" mode). However, the
input may then not see a gap between the second and third page
(staging problem). The printer may print the second page and
continue to feed media in the media path until the sensor is
cleared. Accordingly, the third page may be fed without being
printed on.
[0075] The printer may at this point make a decision of whether to
adapt feeding where picking and gap time may be determined by a
leading edge and a trailing of edge of a sheet of media to pass the
sensor prior to picking the next sheet ("consistent mode").
Regardless of whether this decision is made, the printer may pick
another page so that the third page may be printed on the fourth
sheet. If the printer has been adapted to consistent mode then the
fourth page to be printed may be picked and printed after the
trailing edge of the third page has cleared the input sensor. If
the printer has not been adapted to consistent mode and remains in
page length mode, then the fourth page may be picked based upon the
gap needed for fastest throughput.
[0076] This sequence of events may provide that the finished output
of sheets may have an extra blank page in the output bin due to the
indicated staging problem. Therefore, the number of times that the
system allows a staged sheet to occur before entering consistent
mode may be varied.
[0077] In another exemplary embodiment of adaptation, the printing
device may adapt from "feed time" mode to "consistent" mode, as
illustrated in FIGS. 11 and 12. In FIG. 11 the printing device may
be set to "feed time" mode. At 1110 the power may be turned on to
the printing device or the printing device may be activated from
standby or power save mode. At 1112 a print job may be generated. A
pick signal may be issued at 1114 and a determination may be made
as to whether the sheet of media being printed is a first sheet of
media at 1116.
[0078] If the sheet is a first sheet n, then the sensor may be
activated when the sheet reaches the sensor at 1118 and the feed
time may be measured FTm(n). The measured feed time FTm.sub.(n) may
be set as the expected feed time for the next sheet of media
FTexp.sub.(n+1) at 1120. The value of the expected feed time for
the next sheet of media FTexp.sub.(n+1) may then be used to
calculated a pick delay (PD) according to the relationships
described herein at 1140.
[0079] If it is determined that the sheet is not a first sheet n,
then a determination may be made as to whether the sensor has been
deactivated after a selected period of time for a prior sheet n at
1122. The selected period of time may be any desired time period.
For example, the selected period of time may be a page length (PL).
If the sensor has de-activated for the previous sheet, such as
first sheet n at 1122, then the sensor may be activated when sheet
n+1 reaches the sensor at 1128 and the feed time may be measured
FTm.sub.(n+1).
[0080] A determination may then be made as to whether the measured
feed time for sheet n+1 FTm.sub.(n+1) may be greater than a maximum
feed time FTmax at 1130. If the measured feed time for sheet n+1,
FTm.sub.(n+1) is greater than a maximum feed time FTmax at 1130,
then the feed time expected for the next sheet sheet n+2,
FTexp.sub.(n+2), may be set to the feed time expected for a
previous sheet, such as FTexp.sub.(n+1), at 1132. This value may
then be used to calculate a pick delay for the next sheet, sheet
n+2 at 1140. It should be appreciated that the deactivation of the
sensor between a pick signal and the activation of the sensor may
not affect the measurement of the feed time. Furthermore, depending
on the desired gap, it should also be appreciated that the sensor
may be deactivated prior to the pick signal for a subsequent page
being activated.
[0081] If the measured feed time for sheet n+1, FTm.sub.(n+1) is
not greater than the maximum feed time FTmax, then a determination
may be made at 1134 of whether the measured feed time for sheet
n+1, FTm.sub.(n+1) is less than the expected feed time for sheet
n+1, FTexp.sub.(n+1). If the feed time measured for sheet n+1,
FTm.sub.(n+1) is less than the expected feed time for sheet n+1,
FTexp.sub.(n+1) then the measured feed time FTm.sub.(n+1) may be
set as an expected feed time for the next sheet, sheet n+2,
FTexp.sub.(n+2) at 1136. This value FTexp.sub.(n+2) may then be
used to determine the pick delay for the next sheet, sheet n+2 at
1140.
[0082] If the measured feed time for sheet n+1, FTm.sub.(n+1) is
not less than the expected feed time for sheet n+1, FTexp.sub.(n+1)
at 1134, then the feed time may be adjusted to pick the next sheet,
sheet n+2, sooner at 1138 by adding a factor HB to the feed time.
Accordingly, the feed time expected for the next sheet, sheet n+2,
FTexp.sub.(n+2) may be the expected feed time for the sheet n+1,
FTexp.sub.(n+1) plus a factor HB, wherein
FTexp.sub.(n+2)=FTexp.sub.(n+1)+HB. The value of the expected feed
time for sheet n+2, FTexp.sub.(n+2) may then be used to determine
the pick delay for sheet n+2 at 1140.
[0083] After a pick delay has been determined for the next sheet at
1140, it may be determined whether there is another sheet to be
printed in the print job at 1142. If there is another sheet to be
printed in the print job, the next sheet may be picked at 1114. If
there is not another sheet to be printed, then the sensor may be
deactivated at 1144 and the printing device may wait for a new
print job to be generated at 1112.
[0084] If the sensor has not been deactivated after a selected
period of time at 1122 then the media may be fed until the sensor
deactivates at 1124. A decision may be made regarding whether the
printing device should adapt feeding to another feeding mode, such
as "consistent mode," at 1126.
[0085] If a decision is not made to adapt at 1126, then a new pick
signal may be issued and sheet n+2 may be picked. The information
for sheet n+1 may then be printed on sheet n+2. If a decision is
made to adapt at 1126, then the printing device may begin to feed
in "consistent" mode illustrated in FIG. 12 following step E.
[0086] In FIG. 12, the decision has been made to adapt to
consistent mode and sheet n+2 may be picked at 1210. The printing
device may print on sheet n+2 the information that would have been
printed on sheet n+1. The sensor may be activated at 1212 and then
after sheet n+2 passes the sensor, the sensor may be deactivated at
1214. A determination at 1216 may be made as to whether a sheet n+2
was the final page in the print job. If sheet n+2 is not the final
page sheet n+3 may be picked at 1218 and the input sensor may be
activated at 1212. If sheet n+2 is the final sheet the flow diagram
may continue at F in FIG. 11. The sensor may be deactivated at 1144
(referring to FIG. 11) and the printing device may wait for a new
print job to be generated at 1112.
[0087] It should also be appreciated that the functionality
described herein for the embodiments of the present invention may
be implemented by using hardware, software, or a combination of
hardware and software, either within the printing device or outside
the printing device, as desired. If implemented by software, a
processor and a machine readable medium are required. The processor
may be of any type of processor capable of providing the speed and
functionality required by the embodiments of the invention.
Machine-readable memory includes any media capable of storing
instructions adapted to be executed by a processor. Some examples
of such memory include, but are not limited to, read-only memory
(ROM), random-access memory (RAM), programmable ROM (PROM),
erasable programmable ROM (EPROM), electronically erasable
programmable ROM (EEPROM), dynamic RAM (DRAM), magnetic disk (e.g.,
floppy disk and hard drive), optical disk (e.g. CD-ROM), and any
other device that can store digital information. The instructions
may be stored on medium in either a compressed and/or encrypted
format. Accordingly, in the broad context of the present invention,
and with attention to FIG. 13, the printing device may contain a
processor (1310) and machine readable media (1320) and user
interface (1330). It should be appreciated that the user interface
may be any interface that the user has with the printing device, or
any device that may be in communication with the printing device in
which the user may input into the printing device. Devices in
communication with the printing device may include, but are not
limited to, computers, cameras, storage media, scanners, or other
devices.
[0088] The foregoing description is provided to illustrate and
explain the present invention. However, the description hereinabove
should not be considered to limit the scope of the invention set
forth in the claims appended here to.
* * * * *