U.S. patent application number 13/408086 was filed with the patent office on 2013-08-29 for sheet feeder having curved calibration strip.
This patent application is currently assigned to XEROX CORPORATION. The applicant listed for this patent is Richard Thomas Calhoun Bridges, Simon Neil Jowett. Invention is credited to Richard Thomas Calhoun Bridges, Simon Neil Jowett.
Application Number | 20130221611 13/408086 |
Document ID | / |
Family ID | 48999775 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130221611 |
Kind Code |
A1 |
Jowett; Simon Neil ; et
al. |
August 29, 2013 |
SHEET FEEDER HAVING CURVED CALIBRATION STRIP
Abstract
A sheet feeder apparatus comprises a roller feeding sheets of
media in a process direction, and a transparent platen positioned
after the roller in the process direction. A scanner is positioned
on the scanner side of the transparent platen, and a calibration
strip is positioned on the sheet side of the transparent platen.
The roller feeds the sheets of media over the sheet side of the
transparent platen and the calibration strip. The calibration strip
has a curved end surface having outer ends and a center. The center
of the curved end surface is between the outer ends of the curved
end surface in a cross-process direction. The cross-process
direction is perpendicular to the process direction. The center of
the curved end surface extends further in the process direction
relative to the outer ends of the curved end surface.
Inventors: |
Jowett; Simon Neil;
(Hertfordshire, GB) ; Bridges; Richard Thomas
Calhoun; (London, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jowett; Simon Neil
Bridges; Richard Thomas Calhoun |
Hertfordshire
London |
|
GB
GB |
|
|
Assignee: |
XEROX CORPORATION
NORWALK
CT
|
Family ID: |
48999775 |
Appl. No.: |
13/408086 |
Filed: |
February 29, 2012 |
Current U.S.
Class: |
271/264 |
Current CPC
Class: |
H04N 1/0079 20130101;
H04N 1/0057 20130101 |
Class at
Publication: |
271/264 |
International
Class: |
B65H 5/06 20060101
B65H005/06 |
Claims
1. A sheet feeder apparatus comprising: a roller feeding sheets of
media in a process direction; a transparent platen positioned after
said roller in said process direction, said transparent platen
being positioned relative to said roller to receive said sheets of
media from said roller, said transparent platen having a sheet side
and a scanner side, opposite said sheet side; a scanner positioned
on said scanner side of said transparent platen; and a calibration
strip positioned on said sheet side of said transparent platen,
said scanner obtaining images of said calibration strip through
said transparent platen during calibration of said scanner, said
roller feeding said sheets of media over said sheet side of said
transparent platen and said calibration strip, said calibration
strip having a curved end surface having outer ends and a center,
said center of said curved end surface being between said outer
ends of said curved end surface in a cross-process direction, said
cross-process direction being perpendicular to said process
direction, and said center of said curved end surface extending
further in said process direction relative to said outer ends of
said curved end surface.
2. The sheet feeder apparatus according to claim 1, said outer ends
of said calibration strip being positioned closer to said roller,
relative to a distance said center of said calibration strip is
from said roller.
3. The sheet feeder apparatus according to claim 1, said curved end
surface having a convex shape in said cross-process direction.
4. The sheet feeder apparatus according to claim 1, said
calibration strip further comprising outer ribs positioned further
from said center than said outer ends in said cross-process
direction, said outer ribs extending toward said processing
direction.
5. (canceled)
6. A sheet feeder apparatus comprising: a drive roller feeding
sheets of media in a process direction; a transparent platen
positioned after said drive roller in said process direction, said
transparent platen being positioned relative to said drive roller
to receive said sheets of media from said drive roller, said
transparent platen having a sheet side and a scanner side, opposite
said sheet side; an idler roller positioned after said transparent
platen in said process direction, said idler roller contacting said
sheets of media as said sheets of media travel from said
transparent platen; a scanner positioned on said scanner side of
said transparent platen; and a calibration strip positioned on said
sheet side of said transparent platen, said scanner obtaining
images of said calibration strip through said transparent platen
during calibration of said scanner, said drive roller feeding said
sheets of media over said sheet side of said transparent platen and
said calibration strip, said calibration strip having a curved end
surface having outer ends and a center, said center of said curved
end surface being between said outer ends of said curved end
surface in a cross-process direction, said cross-process direction
being perpendicular to said process direction, and said center of
said curved end surface extending further in said process direction
relative to said outer ends of said curved end surface.
7. The sheet feeder apparatus according to claim 6, said outer ends
of said calibration strip being positioned closer to said roller,
relative to a distance said center of said calibration strip is
from said roller.
8. The sheet feeder apparatus according to claim 6, said curved end
surface having a convex shape in said cross-process direction.
9. The sheet feeder apparatus according to claim 6, said
calibration strip further comprising outer ribs positioned further
from said center relative to said outer ends in said cross-process
direction, said outer ribs extending toward said processing
direction.
10. (canceled)
11. A sheet feeder apparatus comprising: a first drive roller
feeding sheets of media in a process direction; a transparent
platen positioned after said first drive roller in said process
direction, said transparent platen being positioned relative to
said first drive roller to receive said sheets of media from said
first drive roller, said transparent platen having a sheet side and
a scanner side, opposite said sheet side; a second drive roller
positioned after said transparent platen in said process direction,
said second drive roller being positioned relative to said
transparent platen to receive said sheets of media from said
transparent platen; an idler roller positioned between said second
drive roller and said transparent platen, said idler roller
contacting said sheets of media as said sheets of media travel from
said transparent platen to said second drive roller; a scanner
positioned on said scanner side of said transparent platen; and a
calibration strip positioned on said sheet side of said transparent
platen, said scanner obtaining images of said calibration strip
through said transparent platen during calibration of said scanner,
said first drive roller feeding said sheets of media over said
sheet side of said transparent platen and said calibration strip,
said calibration strip having a curved end surface having outer
ends and a center, said center of said curved end surface being
between said outer ends of said curved end surface in a
cross-process direction, said cross-process direction being
perpendicular to said process direction, and said center of said
curved end surface extending further in said process direction
relative to said outer ends of said curved end surface.
12. The sheet feeder apparatus according to claim 11, said outer
ends of said calibration strip being positioned closer to said
roller, relative to a distance said center of said calibration
strip is from said roller.
13. The sheet feeder apparatus according to claim 11, said curved
end surface having a convex shape in said cross-process
direction.
14. The sheet feeder apparatus according to claim 11, said
calibration strip further comprising outer ribs positioned further
from said center relative to said outer ends in said cross-process
direction, said outer ribs extending toward said processing
direction.
15. (canceled)
16. A printer apparatus comprising: a roller feeding sheets of
media in a process direction; a transparent platen positioned after
said roller in said process direction, said transparent platen
being positioned relative to said roller to receive said sheets of
media from said roller, said transparent platen having a sheet side
and a scanner side, opposite said sheet side; a scanner positioned
on said scanner side of said transparent platen; a calibration
strip positioned on said sheet side of said transparent platen,
said scanner obtaining images of said calibration strip through
said transparent platen during calibration of said scanner, said
roller feeding said sheets of media over said sheet side of said
transparent platen and said calibration strip, said calibration
strip having a curved end surface having outer ends and a center,
said center of said curved end surface being between said outer
ends of said curved end surface in a cross-process direction, said
cross-process direction being perpendicular to said process
direction, and said center of said curved end surface extending
further in said process direction relative to said outer ends of
said curved end surface; and a printing engine operatively
connected to said scanner, said printing engine printing images
captured by said scanner.
17. The printer apparatus according to claim 16, said outer ends of
said calibration strip being positioned closer to said roller,
relative to a distance said center of said calibration strip is
from said roller.
18. The printer apparatus according to claim 16, said curved end
surface having a convex shape in said cross-process direction.
19. The printer apparatus according to claim 16, said calibration
strip further comprising outer ribs positioned further from said
center relative to said outer ends in said cross-process direction,
said outer ribs extending toward said processing direction.
20. (canceled)
Description
BACKGROUND
[0001] Embodiments herein generally relate to sheet feeders and
more particularly to sheet feeders used with scanners and
transparent platens that use calibration strips.
[0002] Imaging units in sheet feeders can be particularly sensitive
to cross process magnification errors caused by variation in the
gap between the transparent platen and the sheet throughout the
feed. Two distinct errors are sometimes produced. The first occurs
as the lead edge of the sheet travels past the scan point and
follows the paper path to the exit rolls. The second occurs as the
trail edge falls from the calibration strip. The severity of the
image quality defects is a combination of both the change in the
magnitude of the gap between the sheet and transparent platen and
the rate at which the gap changes. The cross process magnification
errors manifest themselves most as kinks in straight lines at the
inboard or outboard extremities of the sheet.
SUMMARY
[0003] An exemplary sheet feeder apparatus presented herein
comprises a first drive roller feeding sheets of media in a process
direction and a transparent platen positioned after the first drive
roller in the process direction. The transparent platen is
positioned relative to the first roller to receive the sheets of
media from the first roller. The transparent platen has a sheet
side and a scanner side, opposite the sheet side. A scanner is
positioned on the scanner side of the transparent platen, and a
calibration strip is positioned on the sheet side of the
transparent platen. The scanner is positioned adjacent the end of
the calibration strip, and the scanner can be calibrated by images
of the calibration strip obtained through the transparent
platen.
[0004] The first drive roller feeds the sheets of media over the
sheet side of the transparent platen and the calibration strip. The
calibration strip has a curved end surface. The center of the
curved end surface is between the outer ends of the curved end
surface in the cross-process direction (the cross-process direction
is perpendicular to the process direction). The center of the
curved end surface extends further in the process direction,
relative to the outer ends of the curved end surface. More
specifically, the curved end surface has a convex shape in the
cross-process direction and the outer ends of the calibration strip
are positioned closer to the roller, relative to the distance the
center of the calibration strip is from the roller. The calibration
strip further comprises outer ribs positioned further from the
center than the outer ends in the cross-process direction, and the
outer ribs also extend toward the processing direction.
[0005] This sheet feeder also includes a second drive roller
positioned after the transparent platen in the process direction.
The second roller is positioned relative to the transparent platen
to receive the sheets of media from the transparent platen. An
idler roller is positioned between the second drive roller and the
transparent platen. Thus, the idler roller contacts the sheets of
media as the sheets of media travel from the transparent platen to
the second drive roller.
[0006] These and other features are described in, or are apparent
from, the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Various exemplary embodiments of the systems and methods are
described in detail below, with reference to the attached drawing
figures, in which:
[0008] FIG. 1 is a processing direction cross-sectional schematic
diagram of a device according to embodiments herein;
[0009] FIG. 2 is a perspective-view cross-processing direction
cross-sectional schematic diagram of a device according to
embodiments herein;
[0010] FIG. 3 is a perspective-view cross-processing direction
cross-sectional schematic diagram of a device according to
embodiments herein;
[0011] FIG. 4 is an image of an image quality defect according to
embodiments herein;
[0012] FIG. 5 is an image without an image quality defect according
to embodiments herein; and
[0013] FIG. 6 is a processing direction cross-sectional schematic
diagram of a device according to embodiments herein.
DETAILED DESCRIPTION
[0014] As mentioned above, imaging units in sheet feeders can be
particularly sensitive to cross process magnification errors caused
by variation in the gap between the transparent platen and the
sheet throughout the feed. Cross process magnification errors
manifest themselves as kinks in straight lines at the inboard or
outboard extremities of the sheet. For example, as shown in the
image 160 in FIG. 4, a trail edge defect 162 shows up as a rapid
change in the cross process magnification and is most obvious again
on a straight border. This defect coincides with the trail edge of
the sheet falling from the calibration strip close to the scan
point (as shown by the upward arrow in FIG. 3, discussed below). A
flat calibration strip allows the entire width of the trail edge
(122 in FIG. 3) of the sheet to instantaneously fall onto the
platen, which causes a rapid change in cross process magnification
at the scan point. Even though the calibration strip can be very
thin (e.g., 0.3 mm) this error can continue to occur in highly
sensitive systems.
[0015] In view of these issues, this disclosure presents a
structure that allows the extremities of the sheet (inboard and
outboard edges of the sheet) to be gradually released onto the
platen as the trail edge travels over the calibration strip and at
a point further away from the scan point by using a calibration
strip that has a curved end (as shown by item 138 in FIG. 3). This
design uses the beam strength of the sheet to ensure that, as the
centre of the sheet is still supported, the extremities are lowered
onto the glass in a way that has less of an effect on the gap at
the scan point (and this reduces or eliminates the trail edge
defect 162, as shown by the lack of a defect 172 in FIG. 5).
[0016] More specifically, as shown in FIGS. 1-3, an exemplary sheet
feeder apparatus 22 presented herein comprises a first drive roller
110 and opposing bias roller 114 feeding sheets 102 of media in a
process direction (indicated by the block arrow) and a transparent
platen 100 (which can be glass, transparent plastic, transparent
ceramic, etc.) positioned after the first drive roller 110 in the
process direction. The transparent platen 100 is positioned
relative to the first drive roller 110 to receive the sheets 102 of
media from the first roller. The transparent platen 100 has a sheet
side and a scanner side, opposite the sheet side. A scanner 104
(which can be any form of light sensing device, such as a full with
array (FWA) of light sensors, etc.) is positioned on the scanner
104 side of the transparent platen 100, and a calibration strip 130
(which can be any material of suitable reflectivity, such as BoPET
(Biaxially-oriented polyethylene terephthalate), polymers,
polyesters, metals, glasses, ceramics, etc.)) is positioned on the
sheet side of the transparent platen 100. An opposing guide 106
(which can be formed from any of the preceding materials) is spaced
from the calibration strip 130 and the sheet passes between the
calibration strip 130 and the opposing guide 106.
[0017] As shown in FIGS. 1 and 3, the first drive roller 110 feeds
the sheets 102 of media over the sheet side of the transparent
platen 100 and the calibration strip 130. As shown in the
perspective-view schematic diagram in FIG. 2, the calibration strip
130 has a curved end surface 138. The center 132 of the curved end
surface 138 is between the outer ends 134 of the curved end surface
138 in the cross-process direction. The cross-process direction is
perpendicular to the process direction. Again, the process
direction is shown by the block arrows in FIGS. 1-3.
[0018] As shown in FIG. 2, the center 132 of the curved end surface
138 extends further in the process direction, than the outer ends
134 (inboard and outboard ends 134) of the curved end surface 138.
Note that in FIG. 2, the platen 100 is shown in transparent form to
allow the other features to be observed more easily.
[0019] More specifically, the curved end surface 138 has a convex
shape in the cross-process direction, as shown in FIG. 2. The outer
ends 134 of the calibration strip 130 are therefore positioned
closer to the roller 100, relative to the distance the center 132
of the calibration strip is from the roller 100. The calibration
strip 130 can further comprise outer ribs 136 positioned further
from the center 132 than the outer ends 134 in the cross-process
direction, and the outer ribs 136 extends further in the process
direction, than the outer ends 134.
[0020] This sheet feeder 22 also includes a second drive roller 112
and opposing bias roller 116 positioned after the transparent
platen 100 in the process direction. The second drive roller 112 is
positioned relative to the transparent platen 100 to receive the
sheets 102 of media from the transparent platen 100. An idler
roller 140 is positioned at the end of the opposing calibration
strip 106, between the second drive roller 112 and the transparent
platen 100. Thus, the idler roller 140 contacts the sheets 102 of
media as the sheets 102 of media travel from the transparent platen
100 to the second drive roller 112.
[0021] Thus, as shown in FIG. 2, the design of the calibration
strip 130 is negatively scalloped in order to release the
extremities of the sheet 102 slowly onto the transparent platen 100
rather than allowing the trail edge of the sheet 102 to flick
suddenly from the calibration strip 130 in the direction shown by
the upward arrow in FIG. 3. Note that FIG. 3 is a bottom-up
perspective view from beneath the platen 100, relative to the
top-down perspective view shown in FIG. 2.
[0022] The calibration strip 130 can be, for example, cut from a
flat, thin sheet of BoPET (0.2 mm thin) and is adhered to the
platen 100. Together the calibration strip 130 and the platen 100
form the upper portion of the paper path (see FIG. 1). The sheet
102 passes by the calibration strip 130, but due to the geometry of
the exit path, the sheet 102 presses against the calibration strip
130 and platen 100. As the trail edge 122 of the sheet 102 travels
past the ending edge of the calibration strip 130 in the process
direction, the trail edge 122 of the sheet 102 can flick onto the
platen 100, in the direction shown by the upward arrow in FIG. 3.
This sheet movement can cause a rapid change in the gap between the
sheet 102 and platen 100 at the imaging point (note that the
scanner 104 is positioned at the end of the calibration strip 130)
and this sheet movement can cause image quality defects. The curved
shape of the end 138 of the calibration strip 130 is designed to
ensure that the extremities of the sheet 102 (inboard and outboard
edges of the sheet 102, in the cross-process direction) are
released onto the platen 100 in a more controlled fashion and while
the center of the sheet 102 is still in contact with, and supported
by the calibration strip 130 due to the curved design. Therefore,
the curved shape of the end 138 of the calibration strip 130 causes
the inboard and outboard edges of the trailing end 122 of the sheet
102 to move toward the platen 100 before the center of the sheet
102 moves toward the platen 100, thereby making the movement of the
trailing end 122 of the sheet 102 toward the platen 100 more gentle
and reducing the rapid change in cross process magnification at the
scan point (which reduces or eliminates the trail edge defect 162
in item 160 shown in FIG. 4, as shown by the lack of a defect 172
in item 170 in FIG. 5).
[0023] This curved calibration strip 130 can be assisted by the
support provided by an idler roller 140 that is placed after the
scan point at such a point that it supports the sheet 102 and
positively biases the sheet 102 against the transparent platen 100
(as shown in FIG. 1). The positive biasing of the sheet 102 against
the transparent platen 100 by the idler roller 140 helps make the
curved calibration strip 130 solution more robust because the idler
roller 140 causes the sheet 102 position and angle to be more
controlled at the scan point when the trail edge 122 begins to
transition from the calibration strip 130. The positive bias
produced by the idler roller 140 also works to alleviate the effect
of positional tolerances of the constituent parts of the design.
Thus, the combination of the calibration strip 130 and the idler
roller 140 work together to reduce the severity of the trailing
edge defects and to make the design more robust to mechanical
tolerances and noises (such as media weight, curl etc.).
[0024] Referring to the FIG. 6 a printing machine 10 is shown that
includes an automatic document feeder 20 (ADF) that can be used to
scan (at a scanning station 22) original documents 11 fed from a
tray 19 to a tray 23. The user may enter the desired printing and
finishing instructions through the graphic user interface (GUI) or
control panel 17, or use a job ticket, an electronic print job
description from a remote source, etc. The control panel 17 can
include one or more processors 60, power supplies, as well as
storage devices 62 storing programs of instructions that are
readable by the processors 60 for performing the various functions
described herein. The storage devices 62 can comprise, for example,
non-volatile storage mediums including magnetic devices, optical
devices, capacitor-based devices, etc.
[0025] An electronic or optical image or an image of an original
document or set of documents to be reproduced may be projected or
scanned onto a charged surface 13 or a photoreceptor belt 18 to
form an electrostatic latent image. The belt photoreceptor 18 here
is mounted on a set of rollers 26. At least one of the rollers is
driven to move the photoreceptor in the direction indicated by
arrow 21 past the various other known electrostatic processing
stations including a charging station 28, imaging station 24 (for a
raster scan laser system 25), developing station 30, and transfer
station 32.
[0026] Thus, the latent image is developed with developing material
to form a toner image corresponding to the latent image. More
specifically, a sheet 15 is fed from a selected paper tray supply
33 to a sheet transport 34 for travel to the transfer station 32.
There, the toned image is electrostatically transferred to a final
print media material 15, to which it may be permanently fixed by a
fusing device 16. The sheet is stripped from the photoreceptor 18
and conveyed to a fusing station 36 having fusing device 16 where
the toner image is fused to the sheet. A guide can be applied to
the substrate 15 to lead it away from the fuser roll. After
separating from the fuser roll, the substrate 15 is then
transported by a sheet output transport 37 to output trays a
multi-function finishing station 50.
[0027] Printed sheets 15 from the printer 10 can be accepted at an
entry port 38 and directed to multiple paths and output trays 54,
55 for printed sheets, corresponding to different desired actions,
such as stapling, hole-punching and C or Z-folding. The finisher 50
can also optionally include, for example, a modular booklet maker
40 although those ordinarily skilled in the art would understand
that the finisher 50 could comprise any functional unit, and that
the modular booklet maker 40 is merely shown as one example. The
finished booklets are collected in a stacker 70. It is to be
understood that various rollers and other devices which contact and
handle sheets within finisher module 50 are driven by various
motors, solenoids and other electromechanical devices (not shown),
under a control system, such as including the microprocessor 60 of
the control panel 17 or elsewhere, in a manner generally familiar
in the art.
[0028] Thus, the multi-functional finisher 50 has a top tray 54 and
a main tray 55 and a folding and booklet making section 40 that
adds stapled and unstapled booklet making, and single sheet C-fold
and Z-fold capabilities. The top tray 54 is used as a purge
destination, as well as, a destination for the simplest of jobs
that require no finishing and no collated stacking. The main tray
55 can have, for example, a pair of pass-through sheet upside down
staplers 56 and is used for most jobs that require stacking or
stapling.
[0029] As would be understood by those ordinarily skilled in the
art, the printing device 10 shown in FIG. 6 is only one example and
the embodiments herein are equally applicable to other types of
printing devices that may include fewer components or more
components. For example, while a limited number of printing engines
and paper paths are illustrated in FIG. 6, those ordinarily skilled
in the art would understand that many more paper paths and
additional printing engines could be included within any printing
device used with embodiments herein.
[0030] Many computerized devices are discussed above. Computerized
devices that include chip-based central processing units (CPU's),
input/output devices (including graphic user interfaces (GUI),
memories, comparators, processors, etc. are well-known and readily
available devices produced by manufacturers such as Dell Computers,
Round Rock Tex., USA and Apple Computer Co., Cupertino Calif., USA.
Such computerized devices commonly include input/output devices,
power supplies, processors, electronic storage memories, wiring,
etc., the details of which are omitted herefrom to allow the reader
to focus on the salient aspects of the embodiments described
herein. Similarly, scanners and other similar peripheral equipment
are available from Xerox Corporation, Norwalk, Conn., USA and the
details of such devices are not discussed herein for purposes of
brevity and reader focus.
[0031] The terms printer or printing device as used herein
encompasses any apparatus, such as a digital copier, bookmaking
machine, facsimile machine, multi-function machine, etc., which
performs a print outputting function for any purpose. The details
of printers, printing engines, etc., are well-known by those
ordinarily skilled in the art and are discussed in, for example,
U.S. Pat. No. 6,032,004, the complete disclosure of which is fully
incorporated herein by reference. The embodiments herein can
encompass embodiments that print in color, monochrome, or handle
color or monochrome image data. All foregoing embodiments are
specifically applicable to electrostatographic and/or xerographic
machines and/or processes.
[0032] In addition, terms such as "right", "left", "vertical",
"horizontal", "top", "bottom", "upper", "lower", "under", "below",
"underlying", "over", "overlying", "parallel", "perpendicular",
etc., used herein are understood to be relative locations as they
are oriented and illustrated in the drawings (unless otherwise
indicated). Terms such as "touching", "on", "in direct contact",
"abutting", "directly adjacent to", etc., mean that at least one
element physically contacts another element (without other elements
separating the described elements). Further, the terms automated or
automatically mean that once a process is started (by a machine or
a user), one or more machines perform the process without further
input from any user.
[0033] It will be appreciated that the above-disclosed and other
features and functions, or alternatives thereof, may be desirably
combined into many other different systems or applications. Various
presently unforeseen or unanticipated alternatives, modifications,
variations, or improvements therein may be subsequently made by
those skilled in the art which are also intended to be encompassed
by the following claims. The claims can encompass embodiments in
hardware, software, and/or a combination thereof. Unless
specifically defined in a specific claim itself, steps or
components of the embodiments herein cannot be implied or imported
from any above example as limitations to any particular order,
number, position, size, shape, angle, color, or material.
* * * * *