U.S. patent application number 10/693557 was filed with the patent office on 2005-04-28 for adjustable biasing device for sheet media feeder.
Invention is credited to Buibas, Marius, Zhang, Erik Yi.
Application Number | 20050087922 10/693557 |
Document ID | / |
Family ID | 34522421 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050087922 |
Kind Code |
A1 |
Zhang, Erik Yi ; et
al. |
April 28, 2005 |
Adjustable biasing device for sheet media feeder
Abstract
An adjustable biasing device for a sheet media feeder is
disclosed. The adjustable biasing device biases sheets of media
toward a media engaging structure and has an adjustment control for
modulating the amount of force applied by the biasing device to the
sheets of media.
Inventors: |
Zhang, Erik Yi; (San Marcos,
CA) ; Buibas, Marius; (Chula Vista, CA) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD
INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Family ID: |
34522421 |
Appl. No.: |
10/693557 |
Filed: |
October 24, 2003 |
Current U.S.
Class: |
271/160 |
Current CPC
Class: |
B65H 1/06 20130101; B65H
1/12 20130101; B65H 1/24 20130101 |
Class at
Publication: |
271/160 |
International
Class: |
B65H 001/10 |
Claims
1. A sheet media feeder, comprising: a biasing structure to bias
media sheets toward a media engaging structure; and, an adjustment
control operably secured to the biasing structure to adjust a
biasing force applied to the media sheets, wherein said biasing
structure is operably received within an opening.
2. The adjustable biasing device of claim 1, wherein said biasing
structure is a spring.
3. The adjustable biasing device of claim 2, wherein said spring is
a compression spring.
4. The adjustable biasing device of claim 2, wherein said spring is
retractable within said opening defining a retracted position.
5. The adjustable biasing device of claim 4, wherein said
adjustment control extends a portion of said spring from said
opening.
6. The adjustable biasing device of claim 5, wherein: said sheet
media feeder has a frame; said opening is defined by a threaded
collar operably secured to said frame; and, said adjustment control
is a threaded member sized to engage said threaded collar defining
a first direction of rotation of said threaded member relative to
said threaded collar in which said spring is moved toward said
stack to increase the force applied by the spring to said
stack.
7. The adjustable biasing device of claim 6, wherein said threaded
member resists movement in an opposite second direction of
rotation.
8. The adjustable biasing device of claim 4, wherein: said opening
is threaded with a first defined pitch; said spring is a coil
spring having a second defined pitch; and, said spring is operably
received within the threads of said opening in said retracted
position.
9. The adjustable biasing device of claim 8, wherein said first
defined pitch is less than said second defined pitch.
10. The adjustable biasing device of claim 4, wherein said opening
is a threaded opening, and said adjustment control is a threaded
control knob operably secured to said threaded opening.
11. The adjustable biasing device of claim 10, wherein said
threaded control knob has a visual position indicator operably
secured thereto.
12. The adjustable biasing device of claim 10, further including a
strain gauge operably secured to the biasing member.
13. A printer comprising: a biasing device adapted to apply a
biasing force urging a stack of media toward a media engaging
structure; and, an adjustment control operably secured to said
biasing device for adjusting the amount of biasing force urging the
stack of media toward the media engaging structure, wherein said
biasing device is operably received within an opening.
14. The printer of claim 13, further including a media storage
device secured to a chassis.
15. The printer of claim 14, wherein said media storage device is
detachably secured to the chassis.
16. The printer of claim 13, wherein said printer is an ink jet
printer.
17. The printer of claim 13, wherein said sheets of media are
substantially planar cards.
18. The printer of claim 13, wherein: said biasing device is a
spring operably engaging said stack of media; said spring is
retractably received within said opening to define a retracted
portion received within said opening and an extended portion
extending from said opening toward said stack of media; said
retracted portion having a defined length; and, said adjustment
control regulates the defined length of said retracted portion.
19. The printer of claim 18, wherein: said biasing device is a
compression spring having a first end and an opposite second end,
said second end operably engaging said stack of media; said
compression spring retractably received within a opening at said
first end; and, said adjustment control regulates the amount of the
compression spring received within the opening.
20. The printer of claim 19, wherein said second end is detachable
from said stack of media, and said spring is fully retractable
within said opening.
21. A media feeder for a media path bearing device, the media-path
bearing device having a media engaging structure for engaging media
within the media feeder and urging the media along the media path,
the media feeder comprising; a frame operably secured to the
media-path bearing device, the frame having a storage chamber for
storing a plurality of sheets of media in a stack thereby defining
a stack of media, said stack of media positioned adjacent to the
media engaging structure so as to allow individual sheets of media
from said stack of media to be removed one-by-one by the media
engaging structure; a biasing device operably secured to the frame
and extending between the frame and the stack of media so as to
apply a biasing force urging the stack of media toward the media
engaging structure; and, an adjustment control operably secured to
said biasing device for adjusting the amount of biasing force
urging the stack of media toward the media engaging structures
wherein said biasing device is operably received within an
opening.
22. The media feeder of claim 21, wherein said frame is detachably
secured to the media-path bearing device.
23. A media feeder for a media path bearing device, the media-path
bearing device having a media engaging structure for engaging media
within the media feeder and urging the media along the media path
the media feeder comprising: a frame operably secured to the
media-path bearing device, the frame having a storage chamber for
storing a plurality of sheets of media in a stack thereby defining
a stack of media, said stack of media positioned adjacent to the
media engaging structure so as to allow individual sheets of media
from said stack of media to be removed one-by-one by the media
engaging structure, a biasing device operably secured to the frame
and extending between the frame and the stack of media so as to
apply a biasing force urging the stack of media toward the media
engaging structure; and an adjustment control operably secured to
said biasing device for adjusting the amount of biasing force
urging the stack of media toward the media engaging structure,
wherein: said frame comprises a substantially planar base structure
and a cover operably secured thereto to define the media chamber
therein; and, said cover is transparent to allow viewing of said
biasing device therethrough.
24. A media feeder for a media path bearing device, the media-path
bearing device having a media engaging structure for engaging media
within the media feeder and urging the media along the media path.
the media feeder comprising: a frame operably secured to the
media-path bearing device, the frame having a storage chamber for
storing a plurality of sheets of media in a stack thereby defining
a stack of media, said stack of media positioned adjacent to the
media engaging structure so as to allow individual sheets of media
from said stack of media to be removed one-by-one by the media
engaging structure; a biasing device operably secured to the frame
and extending between the frame and the stack of media so as to
apply a biasing force urging the stack of media toward the media
engaging structure; and an adjustment control operably secured to
said biasing device for adjusting the amount of biasing force
urging the stack of media toward the media engaging structure,
wherein: said biasing device is a spring operably engaging said
stack of media; said spring retractably received within a opening
to define a retracted portion received within said opening and an
extended portion extending from said opening toward said stack of
media; said retracted portion having a defined length; and, said
adjustment control regulates the defined length of said retracted
portion.
25. The media feeder of claim 24, wherein: said opening is threaded
defining threads therein having a defined first pitch; said spring
is a coil spring defining coils having a defined second pitch in an
uncompressed position; and, said coils forming the retracted
portion are received within the threads of said opening.
26. The media feeder of claim 25, wherein said defined first pitch
is less than said defined second pitch.
27. A method for biasing sheets of media forming a stack of media
within a media feeder said method comprising: applying a biasing
force substantially normal to the stack of media; removing sheets
of media from the stack of media; and, adjusting the magnitude of
the biasing force applied by the media biasing device to the stack
of media wherein said media biasing device is operably received
within an opening.
28. The method for biasing sheets of media of claim 27, further
comprising: storing the media feeder containing the stack of media
therein without the media biasing device applying a substantial
biasing force to the stack of media; and, operably connecting the
media biasing device to the stack of media prior to using the media
feeder.
29. The method for biasing sheets of media of claim 27, wherein
said biasing device is a compression spring having a first end
received within an opening in the media feeder and an opposite
second end operably engaging said stack of media; and said
adjusting the amount of biasing force step includes comprises:
extending a portion of said compression spring from said opening as
said stack of media is depleted.
30. The method for biasing sheets of media of claim 27, further
comprising detecting the amount of force applied by the biasing
device to the stack of media.
31. The method for biasing sheets of media of claim 27, wherein
said adjusting the amount of biasing force further comprises
positioning a control knob at a predetermined position relative to
a detected size of said stack of media.
32. A sheet media feeder comprising: means for biasing media sheets
toward means for engaging media; and, means for adjusting a biasing
force applied to the media sheets by the means for biasing, wherein
said means for biasing is operably received within an opening.
33. The sheet media feeder of claim 32, wherein said means for
biasing is a spring.
34. The sheet media feeder of claim 32, wherein said means for
adjusting is a threaded control knob operably secured to the means
for biasing and operably received within a threaded opening on the
sheet media feeder.
35. The sheet media feeder of claim 34, wherein said threaded
opening defines a threaded collar.
36. The media feeder of claim 23, wherein said frame is detachably
secured to the media-path bearing device.
37. The media feeder of claim 23, wherein: said biasing device is a
spring operably engaging said stack of media; said spring
retractably received within a opening to define a retracted portion
received within said opening and an extended portion extending from
said opening toward said stack of media; said retracted portion
having a defined length; and said adjustment control regulates the
defined length of said retracted portion.
38. A method for biasing sheets of media forming a stack of media
within a media feeder said method comprising: applying a biasing
force substantially normal to the stack of media; removing sheets
of media from the stack of media; adjusting the magnitude of the
biasing force applied by the media biasing device to the stack of
media; storing the media feeder containing the stack of media
therein without the media biasing device applying a substantial
biasing force to the stack of media; and operably connecting the
media biasing device to the stack of media prior to using the media
feeder.
39. The method for biasing sheets of media of claim 38, wherein
said biasing device is a compression spring having a first end
received within an opening in the media feeder and an opposite
second end operably engaging said stack of media; and said
adjusting the amount of biasing force comprises: extending a
portion of said compression spring from said opening as said stack
of media is depleted.
40. The method for biasing sheets of media of claim 38, further
comprising detecting the amount of force applied by the biasing
device to the stack of media.
41. The method for biasing sheets of media of claim 38, wherein
said adjusting the amount of biasing force further comprises
positioning a control knob at a predetermined position relative to
a detected size of said stack of media.
42. A method for biasing sheets of media forming a stack of media
within a media feeder said method comprising: applying a biasing
force substantially normal to the stack of media; removing sheets
of media from the stack of media; and adjusting the magnitude of
the biasing force applied by the media biasing device to the stack
of media, wherein said biasing device is a compression spring
having a first end received within an opening in the media feeder
and an opposite second end operably engaging said stack of media;
and said adjusting the amount of biasing force comprises: extending
a portion of said compression spring from said opening as said
stack of media is depleted.
43. The method for biasing sheets of media of claim 42, further
comprising: storing the media feeder containing the stack of media
therein without the media biasing device applying a substantial
biasing force to the stack of media; and operably connecting the
media biasing device to the stack of media prior to using the media
feeder.
44. The method for biasing sheets of media of claim 42, further
comprising detecting the amount of force applied by the biasing
device to the stack of media.
45. The method for biasing sheets of media of claim 42, wherein
said adjusting the amount of biasing force further comprises
positioning a control knob at a predetermined position relative to
a detected size of said stack of media.
46. A method for biasing sheets of media forming a stack of media
within a media feeder said method comprising: applying a biasing
force substantially normal to the stack of media; removing sheets
of media from the stack of media; adjusting the magnitude of the
biasing force applied by the media biasing device to the stack of
media; and detecting the amount of force applied by the biasing
device to the stack of media.
47. The method for biasing sheets of media of claim 46, further
comprising: storing the media feeder containing the stack of media
therein without the media biasing device applying a substantial
biasing force to the stack of media; and operably connecting the
media biasing device to the stack of media prior to using the media
feeder.
48. The method for biasing sheets of media of claim 46, wherein
said biasing device is a compression spring having a first end
received within an opening in the media feeder and an opposite
second end operably engaging said stack of media; and said
adjusting the amount of biasing force comprises: extending a
portion of said compression spring from said opening as said stack
of media is depleted.
49. The method for biasing sheets of media of claim 46, wherein
said adjusting the amount of biasing force further comprises
positioning a control knob at a predetermined position relative to
a detected size of said stack of media.
50. A sheet media feeder comprising: means for biasing media sheets
toward means for engaging media; and means for adjusting a biasing
force applied to the media sheets by the means for biasing, wherein
said means for adjusting is a threaded control knob operably
secured to the means for biasing and operably received within a
threaded opening on the sheet media feeder.
51. The sheet media feeder of claim 50, wherein said threaded
opening defines a threaded collar.
52. The sheet media feeder of claim 50, wherein said means for
biasing is a spring.
Description
BACKGROUND
[0001] Sheet media feeders are widely used in a variety of devices
such as in printers, copy machines, facsimile machines and the
like. In general, sheets of media, such a paper, and the like, are
stored in a stack of media, and the sheet media feeder includes
engaging structures, such as a roller or the like, for separating
one sheet from the stack and urging it along a media path of the
device.
[0002] In order to ensure consistent and reliable separation of the
sheet of media from the stack of media, the sheet of media
typically engages the engaging structure within a predefined range
of force between the sheet of media and the engaging structure. If
too much force is applied, the sheet may not separate from the
stack, and if too little force is applied, the sheet may not
properly engage the engaging structures.
[0003] In many situations, it is undesirable to apply a large
biasing force to a large stack of media. For example, where the
individual sheets of media form a vertical stack of media, and
those sheets of media are relatively massive and/or fragile, such
as when they are individual polymer identification cards or the
like being fed through an identification card printer, the weight
of the large stack of media tends to urge the lowest sheet of media
within that stack toward the engaging structure. Accordingly, it
may be unnecessary to apply any additional biasing force to the
stack of media, and such additional force creates extra load to the
engaging structure and ultimately to the driving mechanism causing
system stall.
[0004] Similarly, as the sheets of media are consumed from the
stack of media, the weight of the stack of media is reduced.
Accordingly, the remaining stack of media cannot contribute
significantly to the biasing of the bottom most sheet of media
toward the engaging structure.
[0005] Therefore, the force applied to the stack of media is
desirably sufficient to urge the bottom most sheet of media in the
stack of media toward the engaging structure when the stack of
media is nearly depleted, while still preventing excessive force
from being applied when the stack of media is large. In practice,
this characteristic tends to limit the size or height of the stack
of media allowed within the frame.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a back isometric view of a printer having a sheet
media feeder with a stacked media-biasing device therein in
accordance with an embodiment of the present invention.
[0007] FIG. 2 is an isometric lower view of the sheet media feeder
that is installed on a media engaging structure, with a stacked
media-biasing device of FIG. 1.
[0008] FIG. 3 is a fragmentary top isometric view of the sheet
media feeder of FIG. 2 with a portion of the cover removed to show
internal detail and a possible full stack of media.
[0009] FIG. 4 is the fragmentary top isometric view of the sheet
media feeder with a portion of the cover removed of FIG. 3 showing
a possible substantially depleted stack of media.
[0010] FIG. 5 is an enlarged isometric view of a portion of the
biasing structure of the sheet media feeder of FIG. 2.
[0011] FIG. 6 is a fragmentary cross-sectional view taken along
line 6-6 of FIG. 4.
[0012] FIG. 7 is a fragmentary cross-sectional view taken along
line 7-7 of FIG. 3.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0013] A biasing device 20 for a sheet media feeder 22 that allows
the amount of force applied to a stack of media 10 to be optimized
as the stack of media 10 is depleted is disclosed in FIGS. 1-7.
[0014] 1. Exemplar Media-Path Bearing Device
[0015] Referring to FIG. 1, the sheet media feeder 22 containing
the biasing device 20 is operably secured to a media-path bearing
device 24, such as a printer 24', copier, facsimile machine or the
like. The media-path bearing device 24 shown in FIG. 1 may bean
inkjet printer 24' or other suitable printer containing the sheet
media feeder 22 detachably secured thereto.
[0016] In one implementation, the inkjet printer 24' includes a
chassis 30, the sheet media feeder 22 for supplying sheets of media
32 to the printer 24' via a media path 34, and a movable print
carriage for moving one or more printheads relative to the sheet of
media 32 at a print zone. The sheets of media 32 may be any type of
suitable sheet material, such as paper, card-stock, transparencies,
mylar, foils, and the like, but for convenience, the illustrated
embodiment is described using a substantially planar, polymer card
that includes a planar surface 36 (FIGS. 6 & 7) adapted to be
printed thereon. Such cards are often used to produce
identification badges, driver's licenses, and the like.
[0017] The sheet media feeder 22 moves the sheet of media 32 into
the print zone from a storage chamber 38 along the media path 34,
using a series of motor-driven rollers or the like, here rollers
40a, 40b, which are secured to the printer so as to engage the
detachable sheet media feeder, are shown in FIG. 2. A plurality of
sheets of media 32 forming a substantially vertical stack of media
10 is stored within the storage chamber 38 thereby defining a stack
height 42 (FIG. 7).
[0018] In the print zone, the sheets of media 32 receive ink from a
printhead, which is operably secured to the carriage (not shown).
The carriage is usually driven by a conventional drive belt/pulley
and motor arrangement along a guide rod or the like. The guide rod
defines a scanning direction or scanning axis along which the
printheads traverse over the print zone. The printheads selectively
deposit one or more ink droplets on the planar surface of the sheet
of media located in the print zone in accordance with instructions
from a printer controller, such as a microprocessor, which may be
located within chassis 30.
[0019] The controller may receive an instruction signal from the
microprocessor based on sensors along the media path 34, and from a
host device (not shown). The printhead carriage motor and the media
delivery system drive motor operate in response to the printer
controller, which may operate in a manner well known to those
skilled in the art.
[0020] In other embodiments, a laser print engine or other suitable
print engine may be used instead of an inkjet print engine.
[0021] 2. Sheet Media Feeder
[0022] As shown in FIGS. 2-4, the sheet media feeder 22 may include
a frame 44 defining the storage chamber 38 therein for receiving
the stack of media 10 so as to allow an outer most sheet of media
32 within the stack of media 10 to engage the media engaging
structure 12, such as a roller 40c or the like. Accordingly, the
media engaging structure 12 thereby engages and separates,
one-by-one, individual sheets of media 32 from the stack of media
10, and urges each sheet from the stack of media 10 along the media
path 34.
[0023] The frame 44 can have at least one side 46 and the stack of
media 10 rests within the storage chamber 38 adjacent to the at
least one side 46. In one implementation, the frame 44 has a lower
side 46' and an upper side 48 and the stack of media 10 is stacked
substantially vertically on the lower side 46' with the media
engaging structure 12 positioned adjacent to the lower side 46' as
shown in FIG. 2. The media engaging structure 12 extends through an
opening 50 in the lower side 46' of the frame 44 to operably engage
the lowest most sheet of media 32a within the stack of media 10 and
urge the lowest most sheet of media 32a through a slot 52 in the
frame toward additional downstream rollers 40a, 40b or the like
along the media path 34. The frame 44 can include a base structure
44a with a transparent cover 44b detachably secured thereto thereby
allowing the stack of media 10 to be viewed through the cover
44b.
[0024] The biasing device 20 operably engages the stack of media 10
to bias the stack of media 10 towards the media engaging structure
12. In the illustrated example embodiment, the biasing device 20
applies a force substantially normal to a planar surface 54 on the
stack of media 10, and the amount of force applied by the biasing
device 20 to the stack of media 10 is adjustable so that the amount
of force applied may be optimized as the stack of media 10 is
depleted from the storage chamber 38.
[0025] For example and as shown in FIGS. 3-7, a compression spring
56 can extend between the frame 44 and the stack of media 10, with
a threaded adjustment control 60 operably secured to a first end 62
of the compression spring 56 as shown. The threaded adjustment
control 60 is operably received is within a mating threaded opening
64 on the frame 44 so as to allow the adjustment control 60 to move
toward the stack of media 10 by turning the adjustment control 60
within the threaded opening 64. Accordingly, by turning the treaded
adjustment control 60 in a first direction 68 (FIG. 3), the
adjustment control 60 moves closer to the stack of media 10,
thereby driving out more pitches of the spring 56 against the stack
of media 10 and increasing the amount of force applied to the stack
of media 10.
[0026] In order to prevent the second end 70 of the compression
spring 56 from adversely impacting the upper most sheet of media
32b of the stack of media 10, a spring engaging structure 72 can be
positioned between the stack of media 10 and the second end 70 of
the compression spring 56. In one possible implementation, the
spring engaging structure 72 has a substantially planar member 74
that engages the upper most sheet of media 32b of the stack of
media 10 on a first side 76, and has a protrusion 78 extending from
its opposite second side 80 toward the threaded opening 64. A disk
82 that is sized to engage the second end 70 of the compression
spring 56 is rotatably secured to the protrusion 78. Accordingly,
when the adjustment control 60 is rotated within the threaded
opening 64, the compression spring 56 will necessarily rotate and
cause the second end 70 to spin the disk 82 about the protrusion 78
and thereby prevent the second end 70 from digging into the stack
of media 10 or otherwise hindering rotation of the compression
spring 56 and adjustment control 60. The disk 82 can also include a
strain gauge 84 or the like thereon which is visible through the
frame 44 thereby allowing the amount of force applied by the
compression spring 56 to the stack of media 10 to be monitored and
tuned accordingly.
[0027] The treaded adjustment control 60 can include a knob portion
90 that allows a user to easily grasp and rotate the adjustment
control 60. In one possible implementation, the knob portion 90
includes a position indicator 92 such as an elongate needle portion
or the like to provide a user with a visual indication of the
position of the knob portion 90 relative to the frame 44.
[0028] The threaded opening 64 can be a threaded and tapered collar
64a received within the upper side 48 of the frame 44. The collar
64a can have a threaded length 94 that provides the adjustment
control 60 sufficient range of movement therein so as to allow the
compression spring 56 to provide an optimal force between the stack
of media 10 and the engaging structure 12, even when the stack of
media 10 is substantially depleted or even if only one sheet of
media 32 is remaining from the stack of media 10.
[0029] As shown in FIGS. 6 & 7, the compression spring 56 can
also be retractable within the threads of the threaded opening 64,
thereby defining a retracted position 100 as shown in FIG. 7 and an
extended position 102 as shown in FIG. 6. In one possible
implementation, the pitch 104 of the threaded opening 64 is less
than the pitch 106 (FIG. 5) of an unloaded portion of the
compression spring 56. Accordingly, the retained portion 108 of the
compression spring 56 received within the threaded opening 64 is
compressed to optimize space, while not allowing the retained
portion 108 of the compression spring 56 to contribute to the force
applied to that stack of media 10. Since, only the extended portion
110 of the compression spring 56, that is the portion that extends
between the threaded opening 64 and the stack of media 10 applies a
force to the stack of media 10, the amount of force applied to a
full stack of media 10' (FIG. 7) can be minimized, while still
allowing the force applied to a substantially depleted stack of
media 10" (FIG. 6) to be increased as needed for proper engagement
between the sheet of media 32a and the engaging structure 12.
[0030] The difference in pitch 104 (FIG. 6), 106 (FIG. 5) between
the threaded opening 64 and the uncompressed spring 56 also serves
to limit the direction of rotation of the adjustment control 60.
The adjustment control 60 can be easily rotated in the first
direction 68 within the threaded opening 64 so as to uncoil the
spring 56 from the threaded opening 64 and thereby increase the
amount of force applied by the compression spring 56. However, an
extended compression spring 56 will not as easily be compressed
back into the threaded opening 64 by turning the adjustment control
60 in the opposite second direction, thereby limiting a user's
ability to inadvertently reduce the amount of force applied by the
spring 56 as the stack of media 10 is depleted.
[0031] The adjustability of the biasing device 20 allows a full
stack of media 10' (FIGS. 3 & 7) to be stored within the
storage chamber 38 without compromising the biasing force applied
to a substantially depleted stack of media 10" (FIGS. 4 & 6)
and without applying too much force when the stack of media 10 is
substantially full. Accordingly, an operator need not replenish or
replace the stack of media 10 as frequently for engaging
reliability reasons.
[0032] Moreover, the rectractability of the spring 56 within the
threaded opening 64 also allows the biasing force applied to the
stack of media 10 to be minimized when not needed, such as during
storage and/or shipment of the media feeder 22 containing the stack
of media 10. Common biasing structures usually store and ship the
media feeder containing the stack of media with the compression
spring fully compressed against the stack of media, thereby
applying the maximum biasing force to the stack of media for
extended periods of time. Accordingly, such forces can tend to
damage the sheets of media within the stack, particularly, where
the media are sheets of resilient, polymer cards used for
identification badges and the like.
[0033] 3. Use and Operation
[0034] A user activates the adjustable biasing device 20 by turning
the adjustment control 60 as needed to apply the necessary force to
the stack of media 10. The position indicator 92 and, if installed,
the transparent cover 44b and strain gauge 84 allow the user to see
if the second end 70 of the spring is operably engaging the stack
of media 10 and adjust the biasing force applied as needed.
Moreover if desired, the frame 44 includes surface ornamentation
thereon relative to defined aligned positions of the position
indicator 92 thereby allowing a user to position the knob portion
90 of the adjustment control 60 for a known stack size or the
like.
[0035] In an example embodiment, the sheet media feeder 22 is a
pre-packaged cartridge-style structure that contains a full stack
of media therein. The structure can arrive with the biasing device
20 in its retracted position 100 so as to prevent excessive force
from being applied to the stack of media 10 during initial
transport and storage of the structure. A user obtains a new sheet
media feeder 22 and turns the adjustment control 60 to a defined
position so as to extend the spring 56 from the threaded opening 64
and apply a biasing force to the stack of media 10. The user then
installs the sheet media feeder 22 on the media-path bearing device
24, such as a printer 24' or the like.
[0036] As the printer 24' is used and the sheets of media 32 are
depleted one-by-one, from the stack of media 10, the user turns the
adjustment control 60, so as to maintain a desirable biasing force
on the stack of media 10. If available, the user can align the
position indicator 92 on the adjustment control 60 to defined
positions for the detected stack height 42 of the stack of media
10. This process of adjusting the adjustment control 60 is repeated
as needed during depletion of sheets of media 32 from the stack of
media 10 thereby maintaining optimal biasing force on the stack of
media 10 as it is being depleted.
[0037] Alternatively, in cases where the strain gauge 84 is
installed, the user can position the adjustment control 60 so as to
maintain the force applied to the strain gauge 84 within a
predetermined range. As the detected force drops below a predefined
limit, the user readjusts the position control 60 accordingly so as
to return the force applied to the strain gauge 84 to within the
predetermined range.
[0038] Also, in cases where a transparent cover 44b is installed,
the user can view through the transparent cover 44b the engagement
between the second end 70 of the biasing device 20 and the
substantially planar member 74. Should the second end 70 ever
become disengaged from the substantially planar member, the user
can position the adjustment control 60 so as to move the second end
70 toward the substantially planar member 74, thereby increasing
the biasing force applied to the stack of media.
[0039] In view of the wide variety of embodiments to which the
principles of the invention can be applied, it should be apparent
that the detailed descriptions of exemplar embodiments are
illustrative only and should not be taken as limiting the scope of
the invention. For example, exemplar type of media-path bearing
device is for illustrative purposes only. Accordingly, the claimed
invention includes all such modifications as may come within the
scope of the following claims and equivalents thereto.
* * * * *