U.S. patent application number 12/778203 was filed with the patent office on 2011-11-17 for media transport system turnover mechanism.
Invention is credited to Randy E. Armbruster, Bradley S. Bush, Bradley C. DeCook, Christopher M. Muir, Thomas Niertit.
Application Number | 20110278390 12/778203 |
Document ID | / |
Family ID | 44225516 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110278390 |
Kind Code |
A1 |
Armbruster; Randy E. ; et
al. |
November 17, 2011 |
MEDIA TRANSPORT SYSTEM TURNOVER MECHANISM
Abstract
A media turnover mechanism includes a roller. A first turn bar
is positioned upstream relative to the roller at an angle relative
to a direction of media motion. A second turn bar is positioned
downstream relative to the roller at an angle relative to a
direction of media motion. A first guide is positioned between the
first turn bar and the roller to direct a leading edge of a web of
media toward the roller. A second guide is positioned between the
roller and the second turn bar to direct the leading edge of the
web of media toward the second turn bar. A third guide is
positioned to direct the leading edge of the web of media around
the second turn bar.
Inventors: |
Armbruster; Randy E.;
(Rochester, NY) ; Bush; Bradley S.; (Hilton,
NY) ; Niertit; Thomas; (Webster, NY) ; Muir;
Christopher M.; (Rochester, NY) ; DeCook; Bradley
C.; (Rochester, NY) |
Family ID: |
44225516 |
Appl. No.: |
12/778203 |
Filed: |
May 12, 2010 |
Current U.S.
Class: |
242/615.21 |
Current CPC
Class: |
B41J 15/165 20130101;
B41J 3/60 20130101; B65H 23/32 20130101; B65H 2801/15 20130101;
B65H 23/28 20130101; B65H 2301/522 20130101 |
Class at
Publication: |
242/615.21 |
International
Class: |
B65H 23/32 20060101
B65H023/32 |
Claims
1. A media turnover mechanism comprising: a roller; a first turn
bar positioned upstream relative to the roller, the first turn bar
being positioned at an angle relative to a direction of media
motion; a second turn bar positioned downstream relative to the
roller, the second turn bar being positioned at an angle relative
to a direction of media motion; a first guide positioned between
the first turn bar and the roller to direct a leading edge of a web
of media toward the roller; a second guide positioned between the
roller and the second turn bar to direct the leading edge of the
web of media toward the second turn bar; and a third guide
positioned to direct the leading edge of the web of media around
the second turn bar.
2. The mechanism of claim 1 wherein the second guide includes a
first guide portion located on a first side of the media and a
second guide portion located on a second side of the media.
3. The mechanism of claim 1, wherein a portion of the first guide
is positioned to direct the leading edge of the web of media around
the first turn bar.
4. The mechanism of claim 1, further comprising: a fourth guide
positioned to direct the leading edge of the web of media around
the roller.
5. The mechanism of claim 4, wherein the fourth guide is hinged
such that the fourth guide includes a first position adjacent to
the roller to direct the leading edge of the web of media and a
second position removed from the roller that provides access to at
least a portion of the roller.
6. The mechanism of claim 5, wherein the roller is a driven
roller.
7. The mechanism of claim 6, the roller being a first roller,
further comprising: a second roller including a first position in
which the second roller applies a force to the driven roller and a
second position removed from the driven roller.
8. The mechanism of claim 4, wherein a portion of the fourth guide
extends to the second guide that is located downstream relative to
the roller.
9. The mechanism of claim 1, wherein a wrap of the third guide
relative to the second turn bar is greater than a wrap of the first
guide relative to the first turn bar.
10. The mechanism of claim 1, wherein a wrap of the third guide
relative to the second turn bar varies along a length of the second
turn bar.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Reference is made to commonly-assigned copending U.S. patent
application Ser. No. 12/627,032 filed Nov. 30, 2009 entitled
"MODULAR MEDIA TRANSPORT SYSTEM", by DeCook et al.,
commonly-assigned copending U.S. patent application Ser. No.
12/627,018 filed Nov. 30, 2009 entitled "MEDIA TRANSPORT SYSTEM FOR
NON-CONTACTING PRINTING", by Muir et al., and Ser. No. ______
(Docket 96218), entitled "MEDIA TRANSPORT SYSTEM DRIVE MODULE", by
Armbruster et al. filed concurrently herewith.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a media transport
system and more particularly relates to a mechanism for flipping
the media while in motion in order to switch the relative
orientation of top and bottom surfaces of the moving web media
within the media transport system.
BACKGROUND OF THE INVENTION
[0003] Continuous web printing allows economical, high-speed,
high-volume print reproduction. In this type of printing, a
continuous web of paper or other substrate material is fed past one
or more printing subsystems that form images by applying one or
more colorants onto the substrate surface. Performance criteria for
mechanical apparatus that handle paper or other print media
traveling at high speeds throughout the printing process include
efficiency and speed as well as the capability to maintain precise
registration.
[0004] In a number of systems of this type, both surfaces of the
web media are printed on. After the first side of the media has
been printed upon, the media transport system flips the print media
over while in motion, in order to print onto the other surface of
the web. Subsystems that perform this function have been called
turnover apparatus, turnbar apparatus, or "turnover modules", for
example, and typically consist of an arrangement of fixed or moving
rollers that direct and re-orient the moving web accordingly.
[0005] One difficulty with conventional turnover apparatus relates
to initial feed of the print media by an operator when loading the
machine for a print job. Turnover apparatus often direct the media
over a somewhat complex feed and guidance path, changing path
direction a number of times in order to perform the flipping
function. This path typically extends around and between a number
of rollers and fixed surfaces that are positioned at different
angles and, because the turnover mechanism is often difficult to
see and to access in the first place, it can be a cumbersome
operation often requiring two people to accomplish. Time and
training requirements for this operator function can be
burdensome.
[0006] The capability to feed the leading edge of a print media
roll through the media transport path quickly and accurately can
translate to increased efficiency, reduced cost, and reduced
likelihood of jams, dirt, and other problems for continuous web
printing. Thus, there is a need for an improved leading edge
guidance solution for high-speed, non-contact, continuous web
printers.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to advance the art
of web media handling. With this object in mind, the present
invention provides solutions for improving leading edge guidance
through a continuous web media transport system and, in particular,
through the media turnover mechanism of such a transport
system.
[0008] According to one feature of the present invention, a media
transport system turnover mechanism includes a number of guides for
directing the leading edge of the media through the turnover
mechanism.
[0009] According to another feature of the present invention, a
media turnover mechanism includes a roller. A first turn bar is
positioned upstream relative to the roller at an angle relative to
a direction of media motion. A second turn bar is positioned
downstream relative to the roller at an angle relative to a
direction of media motion. A first guide is positioned between the
first turn bar and the roller to direct a leading edge of a web of
media toward the roller. A second guide is positioned between the
roller and the second turn bar to direct the leading edge of the
web of media toward the second turn bar. A third guide is
positioned to direct the leading edge of the web of media around
the second turn bar.
[0010] One advantage of the present invention is that it provides a
measure of guidance for routing a media web along a travel path,
around and between rollers, surfaces, and other components of the
printing system. Another advantage of the present invention is that
it provides media web guidance without adding constraint to media
edges.
[0011] The invention and its objects and advantages will become
more apparent in the detailed description of the example
embodiments presented below. The invention is defined by the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the detailed description of the preferred embodiments of
the invention presented below, reference is made to the
accompanying drawings, in which:
[0013] FIG. 1 is a schematic side view of a digital printing system
according to an example embodiment of the present invention;
[0014] FIG. 2 is an enlarged schematic side view of media transport
components of the digital printing system shown in FIG. 1;
[0015] FIG. 3 is a top schematic view showing the arrangement of
rollers and surfaces in a turnover mechanism shown in FIG. 2;
[0016] FIG. 4 is a side view of digital printing system components
according to an example embodiment of the invention;
[0017] FIG. 5 is a perspective view of a prior art turnover
mechanism showing media path directions;
[0018] FIG. 6 is a perspective view of the turnover mechanism shown
in FIGS. 3 and 4 showing guide positions between turn bars and the
fixed drive roller;
[0019] FIG. 7 is another perspective view of the turnover mechanism
showing guide positions between turn bars and the fixed drive
roller;
[0020] FIG. 8 is a top view of the turnover mechanism showing guide
positions;
[0021] FIG. 9 is a partial side view of a turnover mechanism
showing components of a media drive module and guides according to
an example embodiment of the invention;
[0022] FIG. 10 is a plan view of a media guide that fits over a nip
roller in the media drive module;
[0023] FIG. 11 is a side view of the media drive module showing a
media guide in an operating position; and
[0024] FIG. 12 is a side view of the media drive module showing the
media guide in a loading position.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The present description will be directed in particular to
elements forming part of, or cooperating more directly with,
apparatus in accordance with the present invention. It is to be
understood that elements not specifically shown or described may
take various forms well known to those skilled in the art.
[0026] The method and apparatus of the present invention provide a
guidance mechanism to improve leading edge feed of the web media
through the set of rollers and drive mechanism of a turnover
apparatus in a continuous web media transport apparatus.
[0027] The method and apparatus of the present invention provide a
turnover apparatus in a digital printing system that transports
continuously moving web print media past one or more digital
printheads, such as inkjet printheads. The apparatus and method of
the present invention are particularly well suited for printing
apparatus that provide non-contact application of ink or other
colorant onto a continuously moving medium. The printhead of the
present invention selectively moistens at least some portion of the
media as it courses through the printing system, but without the
need to make contact with the print media.
[0028] In the context of the present disclosure, the term
"continuous web of print media" relates to a print media that is in
the form of a continuous strip of media as it passes through the
printing system from an entrance to an exit thereof. The continuous
web of print media itself serves as the receiving print medium to
which one or more printing ink or inks or other coating liquids are
applied in non-contact fashion. This is distinguished from various
types of "continuous webs" or "belts" that are actually transport
system components rather than receiving print media and that are
typically used to transport a cut sheet medium in an
electrophotographic or other printing system. The terms "upstream"
and "downstream" are terms of art referring to relative positions
along the transport path of a moving web; points on the web move
from upstream to downstream.
[0029] Referring to the schematic side view of FIG. 1 and enlarged
view of FIG. 2, there is shown a digital printing system 10 for
continuous web printing according to a modular embodiment. A first
module 20 and a second module 40 are provided for guiding
continuous web media that originates from a source roller 12.
Following an initial slack loop 52, the media that is fed from
source roller 12 is then directed through digital printing system
10, past one or more digital printheads 16 and supporting printing
system 10 components. First module 20 has a support structure,
shown in more detail subsequently, that includes a cross-track
positioning mechanism 22 for positioning the continuously moving
web of print media in the cross-track direction, that is,
orthogonal to the direction of travel and in the plane of travel.
In one embodiment, cross-track positioning mechanism 22 is an edge
guide for registering an edge of the moving media. A tensioning
mechanism 24, affixed to the support structure of first module 20,
includes structure that sets the tension of the print media.
Rollers and fixed surfaces A, B, C, D, E, F, G, and H guide the
moving media through first module 20.
[0030] Downstream from first module 20 along the path of the
continuous web media, second module 40 also has a support
structure, similar to the support structure for first module 20.
Affixed to the support structure of either the first or second
module 20 or 40 are one or more angular constraint structures 26,
such as rollers, for setting an angular trajectory of the web
media. Rollers I, J, K, L, M, N, O, and P guide the moving media
through and out from second module 40.
[0031] Still referring to FIGS. 1 and 2, printing system 10 also
includes a turnover mechanism (TB) 30 that is configured to turn
the media over, flipping it backside-up in order to allow printing
on the reverse side. The print media then leaves the digital
printing system 10 and travels to a media receiving unit, in this
case a take-up roll 18. Take-up roll 18 is then formed from the
re-wound printed web media. The digital printing system can include
a number of other components, including multiple print heads and
dryers, for example, as described in more detail subsequently.
Other examples of system components not described herein but common
to such systems include web cleaners, web tension sensors, and
quality control sensors.
[0032] Control logic for the respective digital printing system 10,
shown at control logic processor 90 in the FIG. 2 embodiment,
monitors load cell signals at one or more locations and, in
response, makes any needed adjustment in motor torque in order to
maintain the proper level of tension throughout the system. For the
embodiments of FIGS. 1 and 2, the pacing drive component of the
printing apparatus is turnover mechanism TB 30. There are two
tension-setting mechanisms, one preceding (upstream from) and one
following (downstream from) turnover mechanism TB 30. On the input
side, load cell signals at roller D (FIG. 2) indicate tension of
the web preceding turnover mechanism TB 30; similarly, load cell
signals at roller J indicate web tension on the output side,
between turnover mechanism TB 30 and take-up roll 18. Control logic
for the appropriate in- and out-feed driver rollers at B and N,
respectively, can be provided by an external computer or processor,
not shown in Figures of this application. Optionally, on-board
control logic processor 90, such as a dedicated microprocessor or
other logic circuit, can be used for maintaining control of web
tension within each tension-setting mechanism and for controlling
other machine operation and operator interface functions. As
described, the tension in a module preceding turnover mechanism TB
30 and a module following turnover mechanism TB 30 can be
independently controlled relative to each other, further enhancing
the flexibility of the printing system. In this example embodiment,
the drive motor is included in turnover mechanism TB 30. In other
example embodiments, the drive motor need not be included in a
turnover mechanism. Instead, the drive motor can be appropriately
located along the web path so that tension within one module can be
independently controlled relative to tension in another module.
[0033] Table 1 that follows identifies the lettered components used
for web media transport and shown in FIG. 2. An edge guide, against
which the media is urged laterally so that an edge of the media
contacts a stop, is provided at A. The slack web entering the edge
guide allows the print media to be shifted laterally without
interference without being overconstrained. An S-wrap device SW
provides stationary curved surfaces over which the continuous web
slides during transport. As the paper is pulled over these surfaces
the friction of the paper across these surfaces produces tension in
the print media. In one embodiment, this device allows an
adjustment of the positional relationship between surfaces, to
control the angle of wrap and allow adjustment of web tension.
TABLE-US-00001 TABLE 1 Roller Listing for FIG. 2 Media Handling
Component Type of Component A Lateral constraint (edge guide)
SW--S-Wrap Zero constraint (non-rotating support). Tensioning. B
Angular constraint (in-feed drive roller) C Zero constraint
(Castered and Gimbaled Roller) D* Angular constraint with hinge
(Gimbaled Roller) E Angular constraint with hinge (Gimbaled Roller)
F Angular constraint (Fixed Roller) G Zero constraint (Castered and
Gimbaled Roller) H Angular constraint with hinge (Gimbaled Roller)
TB(TURNOVER) See FIG. 3 I Zero constraint (Castered and Gimbaled
Roller) J* Angular constraint with hinge (Gimbaled Roller) K
Angular constraint with hinge (Gimbaled Roller) L Angular
constraint (Fixed Roller) M Zero constraint (Castered and Gimbaled
Roller) N Angular constraint (out-feed drive roller) O Zero
constraint (Castered and Gimbaled Roller) P Angular constraint with
hinge (Gimbaled Roller) Note: Asterisk (*) indicates locations of
load cells.
[0034] The top view of FIG. 3 shows the arrangement and constraint
pattern, respectively, for turnover mechanism (TB) 30, shown as
part of second module 40 from FIG. 2. Turnover mechanism TB can
optionally be configured as a separate module, with its web media
handling compatible with that of second module 40. The position of
turnover mechanism TB is appropriately between print zones 54 for
opposite sides of the media. Here, a fixed, non-pivoting, drive
roller 32 of this device provides the single angular constraint.
Lateral constraint is provided by the position of the moving web
upstream of stationary turn bar 34, from the left in FIG. 3.
Stationary turn-bars 34 and 36, respectively upstream and
downstream of drive roller 32, are both positioned at diagonals,
approximately 45.degree. angles relative to media motion over input
and output paths and impart no lateral or angular constraint on the
web as it slides over them. The use of a driven roller in the
turnover mechanism, which can be driven independently of drive
rollers B and N, allows the tension in the web to be separately
maintained both upstream and downstream of the turnover mechanism.
Although not shown in FIG. 3, a nip roller can be used in
conjunction with the driven roller to prevent the web from slipping
relative to the driven roller.
[0035] The side view of FIG. 4 shows the position of turnover
mechanism TB 30 within the support structure of module 40. Fixed
drive roller 32 lies behind turn bars 34 and 36 in the arrangement
shown. It can be appreciated that this makes it difficult to access
drive mechanism components for turnover mechanism 30 and
complicates the operator task of feeding the leading edge of the
web media over and around rollers and surfaces of turnover
mechanism 30.
[0036] The enlarged perspective view of FIG. 5 shows an
unobstructed view of the roller and turn bar arrangement of
turnover mechanism 30 components. The web media feeds from the left
and exits downstream to the right. Directions D1-D4 are shown for
reference to more clearly describe web travel relative to roller 32
and turn bars 34 and 36 in the following sequence. The web media,
initially traveling in direction D1, wraps over the first turn bar
34 and then travels in direction D2 in order to feed toward fixed
roller 32. The web then wraps over roller 32 and passes between the
roller 32 and nip wheels (not shown in FIG. 5). The web then heads
back in direction D3, opposite direction D2, toward the second turn
bar 36. Turn bar 36 redirects the web media into direction D4.
[0037] Referring to the perspective views of FIGS. 6 and 7 and top
view of FIG. 8, an improved arrangement of turnover mechanism 30
according to an embodiment of the present invention uses a set of
guides 100, 102, and 104 in order to help alleviate the difficulty
of feeding the leading edge of the web media through turnover
mechanism 30. First guide 100 is positioned between the first turn
bar 34 and drive roller 32 in order to guide the leading edge
toward roller 32 in direction D2, as was described with reference
to FIG. 5. Second guide 102 is positioned between roller 32 and the
second turn bar 36. Second guide 102 helps to guide the leading
edge of the web media coming out from roller 32 in direction D3
(FIG. 5) toward turn bar 36. Third guide 104 is positioned to guide
the leading edge of the media around turn bar 36 and then out of
the turnover mechanism 30 in direction D4 (FIG. 5). FIG. 8 also
shows the position of a motor 130 that drives roller 32 rotation as
part of a media drive module 140. Motor 130 can be remotely
actuable and can have a jog capability to assist the operator in
initial media edge guidance and feeding, as described
subsequently.
[0038] Still referring to FIGS. 6-8, media guides 100 and 102 have
substantially flat portions that extend between the fixed roller 32
and corresponding turn bars 34 and 36 and guide the web media along
a straight path between the roller and its turn bars. Media guide
104 also has a substantially flat portion that extends away from
turn bar 36. In addition, an edge portion of any or all guides 100,
102, and 104 may also provide curvature in order to help guide the
leading edge around the corresponding roller or fixed turn bar
surface. Guide 100, for example, can have a curved portion 118 to
direct the leading edge of the web media around turn bar 34, as
shown in FIG. 6. In another example, guide 104 can have a curved
portion 108 to direct the leading edge of the web media around the
second turn bar 36, as shown in FIG. 6. In the embodiment shown,
curved portion 118 has approximately a 55 degree wrap about turn
bar 34. In the embodiment shown, this is less wrap than the curved
portion 108 of the third guide 104 provides about second turn bar
36.
[0039] It should be noted that the wrap angle for any individual
guide can be varied to provide an advantageous media edge feed
arrangement, based on the design of the turnover mechanism and on
characteristics of the intended print media. The amount of wrap
provided by any of guides 100, 102, and 104 may vary in other ways.
For example, the angular extent of the wrap could vary across the
width of the media path for any of the guides, so that a greater or
lesser amount of wrap is provided toward one edge of the media path
or along the center, for example.
[0040] Referring to the side view of FIG. 9, media traveling toward
fixed, non-pivoting drive roller 32, on top of guide 100 and in
direction D2, is directed along the surface of end portion 106 in
order to help direct the leading edge of the media around fixed
roller 32. FIGS. 8 and 9 also show a fourth guide 110 that provides
a curved surface about roller 32 and is thus positioned to direct
the leading edge of the web of media around roller 32 and into nip
112.
[0041] Once the leading edge of the web has passed through the nip,
the drive roller is turned on at low speed to drive the web
forward. An edge portion 122 of fourth guide 110 extends onto
second guide 102, extending the contact surface for feeding the
leading edge onto the contact surface of guide 102. Media traveling
away from roller 32, onto guide 102 and in direction D3, is
directed by a lower guide surface 107 back toward guide 102,
thereby preventing the leading edge of the web media from wrapping
around drive roller 32. Accordingly, in some embodiments of the
invention, second media guide 102, extending between fixed roller
32 and turn bar 36, can have a first guide portion (either 107 or
102) located on a first side of the web media and a second guide
portion (the other of 107 or 102) for the second side of the media
that helps to reduce or even prevent the media leading edge from
wrapping around turn bar 36. In the same way as first guide 100
with end portion 106 and fourth guide 110 guided the leading edge
of the web around roller 32, second guide 102 and the curved
portion 108 of guide 104 direct the leading edge of the web around
the second turnbar 36.
[0042] Still referring to FIG. 9, fixed roller 32 is a driven
roller provided with a nip roller 114 in the embodiment shown. The
nip roller can be moved by an actuator 120 between two positions,
so that in a first position (as shown in FIG. 9), a force is
applied to roller 32 at a nip 112 and in a second position, nip
roller 114 is backed away from nip 112 and no force is applied at
nip 112. Movement of the nip roller to the second position aids in
removal of web portions from around the drive roller in the event
of a web break. Actuator 120 is remotely actuable in one
embodiment.
[0043] FIG. 10 shows fourth guide 110 of FIGS. 8 and 9 from a rear
view according to one embodiment. Cutouts or windows 124 in the
guide allow guide 110 to fit in place near drive roller 32 without
interfering with nip roller 114. Other types of opening could
alternately be used. In the embodiment of nip roller 114 shown, the
roller is not continuous, but is instead segmented, with a number
of sections shown as wheels 126. Each segment is independently
rotatable in one embodiment. Segments can alternately be castered
and gimbaled to minimize constraint imposed on the moving web
media.
[0044] It is instructive to note that guides 100, 102, 104, and 110
are provided for feeding the leading edge of the web media during
loading by the operator. Once the media leading edge has been fed
through turnover mechanism 30, these guides typically do not
contact the web media. Thus, during printing, guides 100, 102, 104,
and 110 do not provide any constraints to the web media such as
edge constraint, for example, and are compatible with a kinematic
or exact-constraint web transport path, such as that described in
commonly-assigned copending U.S. patent application Ser. No.
12/627,032 filed Nov. 30, 2009 entitled "MODULAR MEDIA TRANSPORT
SYSTEM", by DeCook et al. and commonly-assigned copending U.S.
patent application Ser. No. 12/627,018 filed Nov. 30, 2009 entitled
"MEDIA TRANSPORT SYSTEM FOR NON-CONTACTING PRINTING", by Muir et
al., both incorporated herein by reference.
[0045] Guides 100, 102, 104, and 110 are provided for the leading
edge only and need not extend to cover the full width of the web
media. This allows guides 100, 102, 104, and 110 to be used with a
printing apparatus that accepts web media of various widths. Guides
100, 102, 104, and 110 can be formed from any suitable material,
including metal, plastic, or various sheet materials, for example.
Guides can be perforated or otherwise featured to reduce weight,
increase rigidity, or to aid in their guidance function.
[0046] In one embodiment, guides 100, 102, 104, and 110 are used by
the operator in conjunction with a partially automated media feed
apparatus that allows the operator to feed and direct the leading
edge into proper position with each turn bar or roller mechanism
and use a mechanized sequence to jog the media along the path until
it is fed through turnover mechanism 30.
[0047] In operation, with reference to FIG. 8, the operator follows
a sequence of steps for feeding the web media through turnover
mechanism 30 by steps of: [0048] (i) threading the leading edge of
the web media around first turn bar 34 with the aid of curved
portion 118 and along first guide 100 toward fixed roller 32 and
associated nip 112 (FIG. 9); [0049] (ii) entering a jog command,
such as by depressing a switch, causing roller 32 to rotate
momentarily at a slow speed; [0050] (iii) pushing the leading edge
along the top surface of first guide 100 to urge the leading edge
around drive roller 32 guided by fourth guide 110 until the web is
captured between nip roller 114 and drive roller 32; [0051] (iv)
continuing the jog command and observing drive roller 32 action
that feeds the leading edge onto the top surface of second guide
102, with the web moving back toward the operator; [0052] (v)
threading the leading edge of the web media around second turn bar
36 guided by the curved portion 108 of third guide 104; and [0053]
(vi) terminating the jog command when the leading edge is fed out
from second turn bar 36 along the third guide 104.
[0054] It can be appreciated that steps (i)-(vi) given above are
illustrative and can be modified in a number of ways and augmented
with any of a number of automated operations. An optional operator
switch or other control for enabling jog operation can be provided
with a separate device or provided as part of turnover mechanism
30. Additional rollers or other components can be provided to
support media feed through drive roller 32.
[0055] The turnover mechanism 30 described herein can be used with
a modular printing apparatus arrangement as described earlier with
respect to FIGS. 1 and 2 or with some other printing apparatus
configuration that is not modular. Slack loops are not required
between or within modules or other parts of the system. Slack loops
can be appropriate where a continuous web is initially fed from a
supply roll or as it is re-wound onto a take-up roll, as was
described with reference to the printing apparatus of FIG. 1.
[0056] FIGS. 9, 11, and 12 show various side views of media drive
module 140 according to one embodiment of the present invention.
Fourth guide 110 has at least a first position, adjacent to roller
32 as shown in FIG. 11, used for guiding the lead edge of the web
of media into the nip between the nip roller 114 or nip wheels 124
and the drive roller 32. FIG. 12 shows guide 110 in a second
position, removed from roller 32. This second position is used to
provide access to a portion of roller 32. With the guide in the
second position and the nip roller 114 moved to the second position
by actuator 120, media fragments can be readily removed from around
the drive roller in the event of a media break or media jam at the
drive roller. A hinge 142 or other mechanism enables mechanical
movement of guide 110 between first and second positions.
Alternately various other types of mechanisms could be used to
allow movement between first and second positions, using techniques
well known in the mechanical arts. An optional latch mechanism (not
shown) is used in one embodiment to temporarily hold guide 110 in
its second position during leading edge feed activity. Latching
mechanisms can include magnets, springs, pins, detents, or other
mechanical devices that help to temporarily hold guide 110 in
place. Guide 110 can be self-closing, using gravity,
spring-loading, or magnetic attraction, for example.
[0057] As shown in FIG. 11, guide 110 has a contact surface 144;
guide 102 has a contact surface 146. Contact surface 144 can extend
onto contact surface 146. Alternately, contact surfaces 144 and 146
can be offset relative to each other such that guide 110 ensures
that the media is directed to the proper side of the downstream
guide 102.
[0058] The invention has been described in detail with particular
reference to certain preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the scope of the invention.
PARTS LIST
[0059] 10. Printing system [0060] 12. Media supply roll [0061] 16.
Digital printhead [0062] 18. Media take-up roll [0063] 20. Module
[0064] 22. Cross-track positioning mechanism [0065] 24. Tensioning
mechanism [0066] 26. Constraint structure [0067] 30. Turnover
mechanism [0068] 32. Drive roller [0069] 34, 36. Turn bar [0070]
40. Module [0071] 48. Support structure [0072] 52. Slack loop
[0073] 54. Print zone [0074] 90. Control logic processor [0075]
100, 102, 104. Guide [0076] 106. End portion [0077] 107. Guide
surface [0078] 108. Curved portion [0079] 110. Guide [0080] 112.
Nip [0081] 114. Roller [0082] 118. Curved portion [0083] 120.
Actuator [0084] 122. Edge portion [0085] 124. Opening [0086] 126.
Wheel [0087] 130. Motor [0088] 140. Media drive module [0089] 142.
Hinge [0090] 144, 146. Contact surface [0091] A, B, C, D, E, F, G,
H, I, J, K, L, M, N, O, P. Rollers [0092] D1, D2, D3, D4.
Direction
SW. S-wrap
[0092] [0093] TB. Turnover mechanism
* * * * *