U.S. patent application number 11/415763 was filed with the patent office on 2006-11-02 for apparatus for loading and unloading a supply of plates in an automated plate handler.
This patent application is currently assigned to AGFA CORPORATION. Invention is credited to Laurence S. Blake, James C. Folsom, Ross A. Freeman, Roger A. Jacques, Libor Krupica, David B. Larsen, Robert S. Ring, Philip A. Rombult, Gerald L. Smith.
Application Number | 20060245870 11/415763 |
Document ID | / |
Family ID | 24785786 |
Filed Date | 2006-11-02 |
United States Patent
Application |
20060245870 |
Kind Code |
A1 |
Blake; Laurence S. ; et
al. |
November 2, 2006 |
Apparatus for loading and unloading a supply of plates in an
automated plate handler
Abstract
An apparatus is provided for positioning a plurality of
cassettes within an automated printing plate handler. In a plate
handler, a plurality of cassettes each contain a supply of printing
plates for delivery to an automatic plate-recording device. The
apparatus includes a separate support table for supporting each of
the plurality of cassettes within the plate handler and an elevator
device for moving each of the support tables along a vertical axis
of the automated plate handler. The automated plate handler is
configured to automatically position a selected cassette in a first
position to facilitate removal of the cassette from the handler.
The plate handler further includes a platform, which substantially
forms an extension of the support table supporting the selected
cassette in the first position. The platform provides a second
position, at which the selected cassette is to be one of, loaded or
unloaded. The selected cassette may be filled with a new supply of
plates on the platform or the selected cassette may be removed from
the platform and replaced by another cassette.
Inventors: |
Blake; Laurence S.;
(Peabody, MA) ; Rombult; Philip A.; (Bradford,
MA) ; Krupica; Libor; (Methuen, MA) ; Larsen;
David B.; (Woburn, MA) ; Folsom; James C.;
(Sanford, ME) ; Freeman; Ross A.; (Somersworth,
NH) ; Jacques; Roger A.; (Rochester, NH) ;
Ring; Robert S.; (Rochester, NH) ; Smith; Gerald
L.; (Dover, NH) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
TWO PRUDENTIAL PLAZA, SUITE 4900
180 NORTH STETSON AVENUE
CHICAGO
IL
60601-6780
US
|
Assignee: |
AGFA CORPORATION
Wilmington
MA
|
Family ID: |
24785786 |
Appl. No.: |
11/415763 |
Filed: |
May 2, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
10807085 |
Mar 23, 2004 |
7055431 |
|
|
11415763 |
May 2, 2006 |
|
|
|
09615931 |
Jul 13, 2000 |
6726433 |
|
|
10807085 |
Mar 23, 2004 |
|
|
|
08693712 |
Aug 7, 1996 |
6113346 |
|
|
09615931 |
Jul 13, 2000 |
|
|
|
08690699 |
Jul 31, 1996 |
5738014 |
|
|
09615931 |
Jul 13, 2000 |
|
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Current U.S.
Class: |
414/411 |
Current CPC
Class: |
B65H 2220/02 20130101;
B65H 2220/01 20130101; B65H 3/54 20130101; B65H 2405/35 20130101;
B65H 3/44 20130101; B65H 2801/21 20130101; B65H 2511/40 20130101;
G03F 7/24 20130101; G03F 7/20 20130101; B65H 2511/40 20130101; B41C
1/1083 20130101; B65H 2511/20 20130101; B65H 2405/332 20130101;
B65H 3/0816 20130101; B65H 2511/20 20130101; B65H 2511/20 20130101;
B65H 2701/1719 20130101; B65H 2511/10 20130101; G03F 7/2014
20130101; B65H 2701/18264 20130101; G03F 7/2055 20130101; B65H
1/266 20130101; B65H 1/14 20130101; B65H 2301/42256 20130101; B65H
2701/1928 20130101; B65H 2511/10 20130101; B65H 2220/02 20130101;
B65H 2220/11 20130101; B65H 2220/01 20130101 |
Class at
Publication: |
414/411 |
International
Class: |
B65B 69/00 20060101
B65B069/00 |
Claims
1.-13. (canceled)
14. An automatic computer-to-plate platesetter for making plates
comprising: a digital file of an image; a plurality of plate
stacks, each plate stack having printing plates of a particular
plate characteristic; a plurality of plate support tables, wherein
each of the support tables corresponds to and supports each plate
stack; an imaging engine that has an imaging drum and a laser to
directly image the digital file onto a printing plate and a command
generator in communication with the plate handler; an elevator that
automatically positions the plate support tables and plate stacks
between lower and upper levels, wherein the elevator positions, in
response to a signal from the command generator requesting a
particular plate, a desired plate stack having a desired plate
characteristic to an access level located between the upper and
lower levels which permits access to the desired plate stack; an
automatic plate picker that automatically removes a first desired
plate from the plate stack at the access level and delivers the
first desired plate directly to the imaging engine wherein the
imaging engine images the digital file onto the first desired plate
to form an imaged plate; and wherein the elevator positions the
plate support tables to an intermediate level located between the
lower and upper levels and supports the plate support tables for
horizontal movement into and out of the elevator so that plate
stacks may be placed on and removed from the plate support
table.
15. The computer-to-plate platesetter as set forth in claim 14,
further comprising a front end in communication with the imaging
engine for sending an input command that identifies the plate
characteristic required by the digital file.
16. The computer-to-plate platesetter as set forth in claim 14,
wherein the plate stacks are moved in a substantially vertical
direction by the elevator.
17. The computer-to-plate platesetter as set forth in claim 14,
further comprising a slip sheet detector for detecting whether a
slip sheet is present on top of the plate stack at the access
level.
18. The computer-to-plate platesetter as set forth in claim 14,
further comprising a slip sheet removal mechanism for removing a
slip sheet when present on top of the plate stack at the access
level.
19. The computer-to-plate platesetter as set forth in claim 14,
wherein the plate picker moves substantially horizontally with
respect to the plate stack at the access level to transfer the
first desired plate to the imaging engine.
20. The computer-to-plate platesetter as set forth in claim 14,
further including means for maintaining a light tight interior
within the platesetter.
21. The computer-to-plate platesetter as set forth in claim 14,
further comprising printing plates which are photosensitive.
22. The computer-to-plate platesetter as set forth in claim 14,
further comprising printing plates which are thermal plates and
imaged by the laser.
23. The automatic computer-to-plate platesetter as set forth in
claim 14 wherein an actuator moves the plate picker towards the
table so the plate picker may engage the desired plate.
24. The automatic computer-to-plate platesetter as set forth in
claim 14 wherein an actuator moves at least one of the table and
the plate picker in at least one of a vertical and horizontal
direction towards each other so that the plate picker may engage
the desired plate.
25. The automatic computer-to-plate platesetter as set forth in
claim 14 wherein an actuator moves the plate picker in a generally
horizontal direction towards the table so that the plate picker may
engage the desired plate.
Description
[0001] This application is a continuation application of commonly
assigned U.S. patent application Ser. No. 10/807,085, filed Mar.
23, 2004; which is a divisional of U.S. Pat. No. 6,726,433, filed
Jul. 13, 2000; which is a divisional of U.S. Pat. No. 6,113,346,
filed Aug. 7, 1996; and U.S. Pat. No. 5,738,014, filed Jul. 31,
1996, all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] Printing processes utilize a vast array of different
technologies to transfer written content to various distribution
media. Organizations using varying printing processes include
modest-volume quick printers, book and financial publishers,
newspaper companies, forms companies, all sizes of commercial
printers (for advertising etc.), and, publication printers (for
magazines and periodicals). These types of organizations have a
common process whereby information is transferred from some
original layout form to an intermediate aluminum or polyester plate
material which is then hung on a standard printing press to enable
multiple identical replication of that information on paper or some
similar print media.
[0003] This process has typically been performed by optically
creating a polyester film which contains the information, optically
transferring the information from the film to a plate material by
use of a light transfer or contact to a light-sensitive chemical
emulsion which is bonded to the plate, and then hanging the
developed plate on a press in alignment (one for each color
separation desired). The plates rotate along with the press
cylinder and alternately come in contact with ink rollers and then
an intermediate transfer blanket. The ink which is accepted by the
transfer blanket then transfers the information to the paper during
rotational contact.
[0004] Recently the development of computer-to-plate, hereinafter
C2P, systems and processes have provided alternative printing
options. The C2P process eliminates the film as an intermediate
transfer mechanism and allows the optical exposure of the plate
directly. This reduces the number of steps required in the printing
process of the information and potentially reduces the cost related
to the generation of the intermediate film and its handling. C2P
systems more readily allow a process which creates plates for
shorter-run printing (below around 50,000 impressions).
[0005] In basic terms, a C2P system accepts input jobs/pages
written in a page description language, for example,
POSTSCRIPT.RTM.. These jobs are controlled through execution by
priority and scheduling workflow software. Jobs are then sent
through a raster image processor to a platemaker for exposure. The
data is being transformed throughout this process. The platemaker
engine takes this data and prints it on a metal sheet of aluminum
which is later notched, bent, hung on the press, inked and made
ready to image paper. An imaging engine and process for imaging a
plate is described in commonly owned U.S. Pat. No. 5,345,870,
hereby incorporated by reference into the present application.
[0006] The inclusion of a C2P system into a printing operation
suggests a greater extent of automation which can be achieved. A
full C2P process can automate, through the use of computers and
special equipment, the transfer of information from the original
layout to the press plate. As such, C2P is not only an improvement
in the specialized equipment but also in the process which utilizes
that equipment. Viewing C2P as a process includes a high level of
workflow management to replace manual effort with computer-driven
effort with a goal to increase productivity and efficiency.
Workflow encompasses such concepts as queue management, color
calibration, revision control, press consumables control, inventory
tracking, job and cost tracking, etc.
[0007] Also included in the automation of a C2P system is the media
handling. It is necessary to supply plates individually from a
plate supply area to the platemaker engine and it is desirable to
reduce the amount of operator handling involved. Unexposed plates
are normally supplied in packages of 25 to 100 with interleaf
sheets between the plates for protecting the sensitive emulsion
side of the plates, which is extremely sensitive to scratches. The
stack of plates needs to be loaded into a supply area of a
platemaker in a manner to keep the stack of plates aligned with
automation mechanisms for removing a plate from the stack, and for
discarding the interleaf sheet from the stack. These functions are
optimally performed within a covered light-tight environment to
prevent unintentional exposure of the light sensitive plate
surface. The platemaker engine requires plates of varying sizes and
formats on demand. It is beneficial to present a variety of plate
sizes and formats to an automated mechanism for selecting the plate
needed by the platemaker engine. It is important to be able to
reload the plate supply area without interrupting the operation of
the platemaker engine. These functions generally will maximize the
output of the platemaker engine, by eliminating time which an
operator would manually handle the plates and during which the
platemaker engine might be interrupted.
[0008] Accordingly it is an object of the present invention to
provide an automated C2P system having a workflow software capable
of controlling and sequencing the tasks performed by the C2P system
from accepting a job input to the system as POSTSCRIPT.RTM. and
output the job from the system as exposed images on printing
plates.
[0009] It is a further object of the invention to increase
productivity and efficiency in a C2P system by providing automated
queue management.
[0010] It is a specific object of the invention to automate the
operation of supplying plates on demand from a plate storage area
within a C2P system to the platemaker engine.
[0011] It is a further object of the invention to provide a plate
handling mechanism to position a plurality of plate cassettes
containing varying plate sizes within the plate storage area,
making a desired plate cassette accessible to a plate picking
mechanism.
[0012] It is another object of the present invention to
automatically remove and discard the interleaf sheets from between
plates after a plate is individually removed from the stack of
plates.
[0013] It is another object of the invention to automatically pick
a plate from the top of a stack of plates and deliver the plate to
the platemaker engine in a manner which accommodates a variety of
plate sizes and formats.
SUMMARY OF THE INVENTION
[0014] A method for handling, loading and unloading a plurality of
cassettes containing a supply of plates in an automated plate
handler includes supporting each cassette on a support table within
the plate handler. The support tables and the cassettes of plates
supported on the tables are automatically positioned in order to
place a cassette to be removed from the plate handler in a cassette
loading position. The cassette to be removed is moved horizontally
along the table onto a loading platform adjacent to the cassette
loading position guiding the cassette to be removed off of the
support table and onto the loading platform while removing the
cassette from the plate handler.
[0015] An apparatus for handling, loading and unloading a plurality
of cassettes containing a supply of plates in an automated plate
handler includes support tables supporting each of the cassettes
within the plate handler. The support tables and the cassettes of
plates on the support tables are automatically positioned in order
to place a cassette to be removed from the plate handler in a
cassette loading position. The cassette to be removed is moved
horizontally by a first mechanism along the table and onto a
loading platform adjacent to the cassette loading position. A guide
member guides the cassette to be removed off of the support table
and onto the loading platform while the cassette is removed from
the plate handler.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The objects and features of the invention will be better
understood and further objects and advantages of the invention will
become apparent in the following detailed description of the
invention, when taken with the accompanying drawing(s), in
which:
[0017] FIG. 1 is a schematic illustration of an electronic prepress
system employing a platesetter shown from a side view with a plate
handler and plate picker mechanism according to the present
invention;
[0018] FIG. 2 is a partial sectional front view of the plate
handler viewed in FIG. 1;
[0019] FIG. 3 is an isometric view of an assembly portion of the
plate handler shown in FIG. 2, particularly featuring an elevator
mechanism and a table supporting mechanism according to the present
invention;
[0020] FIG. 4 is a detailed isometric view of the plate picker
mechanism shown in FIG. 1;
[0021] FIG. 5 is a simplified top view of the picker mechanism of
FIG. 4 positioned over a handler cassette within the plate handler
according to the present invention;
[0022] FIG. 6 is a side view of a portion of the plate handler
showing the plate picker in the process of picking a plate from a
cassette, and also featuring a slip sheet removal mechanism
according to the present invention;
[0023] FIG. 7 is an isometric view of a plate cassette used in the
plate handler according to the present invention; and
[0024] FIG. 8 is a detailed side sectional view of a portion of a
plate cassette as shown in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The computer to plate imaging system shown in FIG. 1 and
generally referred to as reference number 10, is a complete system
for plate production, where digital data files representing a
publication (or printed image) are input to the system 10, and
plates ready to go on a printing press are output from the system
10. Most of the operation of the system is automated, requiring a
minimum of operator intervention. The system is comprised of a
front-end server 12, a raster image processor (RIP) 14 and a
platemaker or platesetter 16. The front-end 12 sends jobs to the
platesetter 16. The platesetter 16 has three major components. An
optional on-line plate handler 18, the imaging engine 20 and an
optional on-line plate processor/plate stacker 22. The plate
handler 18, hereinafter handler, contains a supply of plate
containers or cassettes 24. The handler can hold as little as two
cassettes or as many as three, four, or five depending on user
requirements. Each cassette is a light tight container that houses
a stack of plates 26. The cassettes 24 can be vertically adjusted
by the handler 18 to make plates 26 stored within a particular
cassette available to a plate shuttle mechanism 28, hereinafter
referred to as the picker 28. The picker 28 removes a single plate
from the selected cassette and transports the plate between the
handler 18 and the engine 20, which will be described in detail
hereinafter.
[0026] The primary function of the handler 18 is to make plates 26
available on demand to the imaging engine 20. A multitude of plates
26 are stacked in each cassette 24 and the cassettes 24 are
side-loaded into the handler 18 by an operator. Between each plate
in a stack there may be a protective interleaf sheet or slip sheet
which is removed by the handler 18 and discarded by a slip sheet
removal mechanism 25. The handler 18 receives commands from the
engine 20 by workflow software, which provides instructions to the
handler 18 about what cassette 24 needs to be accessed to make a
plate available to the picker 28 so the plate may be conveyed to
the imaging engine 20. The handler 18 in turn provides status
information to the engine 20 through the workflow software to make
full interaction with the system 10 possible.
[0027] The front-end 12 sends data to the engine 20 through an
interface connection. Typically this data represents a "job" which
requires the imaging of plates. This data contains information
about the job's requirements, such as the type of plate, its size
and plate thickness, the number of plates that are part of the same
job, etc. The engine 20 interfaces electrically with the handler 18
to exchange machine functional and operation data which is input
into the workflow software. The handler 18, through the engine 20,
sends data to the workflow software from data stored in each loaded
cassette 26 representing plate size and quantities available in the
cassettes 24. The handler 18 includes a device 61 for reading an ID
tag 187, for example, a conventional bar-code reader on each
cassette which has a description of the plate type inside. This ID
tag 187 is in the form of a bar-code or other means. If a required
plate size is unavailable, the engine 20 notifies an operator
through a platemaker control terminal 30, so the operator can load
the needed cassette into the handler 18. The engine 20 passes
information to the handler 18 defining the next plate size or
thickness required for imaging and which cassette 24 is to be
placed in the queue, or in the correct position for access by the
picker 28. The cassettes 24 store different sizes and/or
thicknesses of plates 26 so the handler 18 positions a specific
cassette 24 so that the picker 28 can access the required plate
inside the specific cassette. The handler 18 insures the slip
sheet, if present, has been removed from the surface of the top
plate with the slip sheet removal mechanism 25. The picker 28 then
moves over the positioned cassette, the plate is "picked," and the
picker 28 returns to the imaging engine (home) position to deliver
the plate. The imaging engine 20 accepts the plate and while the
picker is in the engine 20 in the home position, the handler 18 is
free to position the cassettes 24 in preparation for the next plate
to be imaged.
[0028] Referring to FIG. 2, some basic elements of the handler 18
are shown. The handler 18 has a support frame 32 which surrounds
several tables 34, 36. The lowermost table 36 is attached to and
supported by a brace 38 on the underside of the lowermost table 36.
The brace 38 is attached to an elevator mechanism, referred to
generally as 40 and to be described hereinafter, which raises and
lowers the brace 38 and the lowermost table 36 supported by the
brace 38. The upper three tables 34 positioned above the lowermost
table 36 rest upon the lower table 36 on table spacers 42 which are
secured to the outer ends of the undersides of the upper three
tables 34. In FIG. 2, the upper three tables 34 are shown being
supported by a table support mechanism, referred to generally as 44
and to be described hereinafter, which separates the tables to
allow clearance space for the picker to enter into above the
cassette from which a plate is going to be picked. When the table
support mechanism 44 is inactive, the table spacers 42 contact the
table immediately below the table which the spacers are attached
to, in a manner so as to support that table. The tables 34, 36 can
be positioned by the elevator mechanism 40 as a group, with the
three upper tables 34 resting on the lowermost table 36 on the
brace 38 of the elevator mechanism 40.
[0029] Referring additionally to FIG. 3, the support frame 32 has
four vertical support beams 46 provided with guide tracks 48 for
guiding the tables while being raised or lowered. Each table has
four rotatable guide wheels 50 (only two shown as viewed in FIG. 2)
which ride in the guide tracks 48 at the corners of each table. The
table support mechanism 44 comprises four vertical shafts 52 with
bearing mounts 54 at the upper ends of each shaft 52. The shafts 52
are rotatable relative to the bearing mounts 54 which are attached
to the topside of the support frame 32. The support frame 32 has
bores (not shown) which the shafts pass through to extend downward
to the tables 34, 36. At the lower ends of the shafts 52 are
support bars 56 which protrude horizontally outward from the shaft
52 at a right angle therefrom, and lower bearing mounts 58 attached
to the four vertical support beams 46. In an inactive position, the
support bars 56 face outward and away from the tables, as shown in
FIG. 3. A linkage 60 connecting the shafts 52 transmits rotary
motion from a drive motor 62 to rotary plates 64 fixed to the tops
of each shaft 52 and to the shaft of the drive motor 62. Upon a
predetermined rotation by the drive motor 62, the linkage 60
connecting the rotary plates causes the four shafts 52 to rotate 90
degrees, positioning the horizontal support bars 56 facing inward
toward the tables, in the active position as in FIG. 2. The support
bars 56 are in position to support the tables 34 above the cassette
24 to be accessed by the picker 28.
[0030] The elevator mechanism 40 comprises a chain drive system
having four chain drives 66, one mounted on each support beam 46.
Two rotatable sprockets 68, 70 are mounted on each support beam 46
in an upper and lower position to cooperate with the chains 66 and
transmit rotary motion of the sprockets 68, 70 into linear motion
of the chains 66. The lower sprockets 70 are attached to two
horizontal shafts 72 which transmit rotary motion from a main drive
shaft 74 through several gear boxes 76 and couplings 78. The main
drive shaft 74 is powered by a drive motor 80 through a belt 82 and
pulley 84 connection.
[0031] The brace 38 is connected to the chains 66 on the inner
sides of the support beams 46 so that upon rotation of the drive
motor 80, the chain drive system raises or lowers the brace 38, the
lowermost table 36, and any upper tables 34 resting thereon which
are not supported by the table support mechanism 44 at the
time.
[0032] Referring now to FIG. 4, the picker 28 is shown supported on
parallel rails 90 which are fixed to the interior of the engine
compartment 20 (FIG. 1). Complementary rails 92 are mounted inside
of the handler 18 as shown cross section in FIG. 2 and
isometrically in FIG. 3, allowing the picker to move smoothly
between the engine 20 and handler 18. The rails 92 inside the
handler are secured to the support beams 46 of the handler frame
32. The picker 28 has a carriage 94 which is supported on the rails
(90 or 92 depending on whether the handler is in the engine or the
picker respectively) by three guide wheels 96 which engage the
rails 90 (or 92) on each side of the carriage 94. Also two friction
wheels 98 engage the rails 90 (or 92). The friction wheels 98 are
driven by a motor 100 mounted on the carriage 94 through a
connection to a drive shaft 102 and a belt and pulley mechanism 104
on each side of the carriage 94. The motor 100 operates in two
directions to effectively propel the picker carriage 94 in forward
and reverse from the engine compartment 20 to the handler 18. The
carriage 94 supports three rows 106, 108, 110 of suction cups and
an associated vacuum manifold 112 and vacuum tubing (not shown)
between the manifold 112 and the three rows 106, 108, 110 of
suction cups. Three manifold vacuum switches 113 connect to vacuum
manifold 112 via vacuum hoses (not shown) to sequence vacuum to
rows 106, 108 and 110 while a bi-directional motor 111 operates a
movably disposed manifold plunger 115 to sequence vacuum to the
suction cups 114 according to the size of the single plate being
picked. The suction cups 114 are mounted on spring loaded fittings
116 to allow compression of the suction cups 114 against a plate
during picking to ensure attachment of the plate to the picker 28.
The first row 106 of suction cups that extends the furthest into
the handler 18 is pivotable with respect to the carriage 94. An
eccentric drive 118 and linkage 120 pivots the first row 106 of
suction cups in a "peeling" motion. The eccentric 118 is driven by
a motor 122 mounted on the carriage 94 to break or peel the edge of
the plate being picked away from the stack. The middle row 108 of
suction cups remains fixed with respect to the picker carriage 94.
The third row 110 of suction cups slides out from the middle row
108 of suction cups. Two rails 124, 126 are mounted for sliding
through complementary bearings (not shown) in the carriage body 94
on the both sides of the picker 28. On the right side of the picker
viewed in FIG. 4, the rail 126 has a friction drive wheel (not
shown) in driving contact with the rail 126. The drive wheel is
driven by a drive motor 128 through a belt and pulley mechanism
(not shown), all of which are mounted to the carriage body 94 so as
to transmit rotary motion of the drive wheel into linear motion of
the rails 126, 124 relative to the carriage body 94. The third row
110 of suction cups being movable relative to the other rows 106,
108 of suction cups expands the overall size of the picker 28 and
the coverage area of the suction cups 114 to accommodate for
various sized plates.
[0033] FIG. 5 illustrates a simplified top view of the picker 28
positioned over a cassette 24 in the handler. The first row 106 of
suction cups 114 is positioned near an inner edge 130 of the
cassette 24 against which the plates are referenced regardless of
the plate size. Four different plates having different sizes are
depicted by dashed lines and are indicated as plates A, B, C, and
D. Plate A is the smallest plate and the middle row 108 of suction
cups of the picker 28 is positioned near the opposite edge 132 of
plate A from the reference edge 130. Vacuum is sequenced to four
suction cups 114, two within row 106 and two within row 108
according to the size of plate A. The middle row 108 has a fixed
position relative to the first row 106 (excepting that the first
row is pivotable) to pick up plate A without the use of the third
row 110 of suction cups. The third row 110 is shown in an extended
position by solid lines, at the far edge 134 of the largest plate D
opposite from the reference edge 130. The third row 110 of suction
cups is also shown by dashed lines in a non-extended position. The
third row 110 of suction cups is used to expand the size of the
picker 28 to cover the areas for various size plates, such as B, C,
and D, larger than the smallest plate A and smaller than or equal
to the largest plate D, as indicated by arrow 136. Vacuum is
sequenced to the suction cups 114 within rows 106, 108 and 110
according to the size of plats B, C and D. Arrow 138 shows the
relative movement of the picker 28 including all three rows 106,
108, 110 of suction cups 114 with respect to the handler cassette
24 and the engine.
[0034] Referring now to FIG. 6, the slip sheet removal mechanism is
generally indicated as 25. The mechanism 25 is for the purpose of
preventing a slip sheet 140 from sticking to the bottom of a plate
142 which is attached to the picker 28, securing the slip sheet 140
on the top of the stack of plates in a cassette 24 to the slip
sheet removal mechanism 25, and subsequently completely removing
the slip sheet 140 from the stack of plates in the cassette 24. The
mechanism 25 comprises a plurality of suction tubes 144 mounted on
a first pivotable shaft 146, an optional peeler air blast 148, a
plurality of fingers 150 mounted on a second pivoting shaft 152, a
plurality of nip wheels 154 mounted on a third pivoting shaft 156
(only one of each seen in drawing due to side view), and a
rotatably driven roller 158 positioned below the nip wheels 154
which are in rolling contact during part of the slip sheet removal
process, to be described hereinafter. A slip sheet detector device
902 is provided on one of the plurality of suction tubes 144. The
detector device 902 provides a signal which is calibrated to
provide a slip sheet present or not present condition to the
handler 18. The suction tubes 144 are fixed to the pivoting shaft
146 to pivot upon being driven by motor 160 through a drive belt
and pulley connection 162. The fingers 150 are fixed to pivoting
shaft 152 which is driven by a similar drive connection to a motor
(not shown). The nip wheels 154 are each mounted to an extension
arm 164 which is attached to a bracket 166 mounted on the pivoting
shaft 156. The extension arm 164 is spring loaded at the connection
to the bracket to allow for the extension arm 164 to pivot or give
slightly while pressure is applied between the nip wheel 154 and
the roller 158. The shaft 156 is rotated in forward and reverse by
the drive motor 168 through a drive belt and pulley connection 170.
The roller 158 is driven by a motor 172 also through a belt and
pulley connection 174. It will be understood by those skilled in
the art that equivalent means for rotating the pivoting shafts 146,
152, 156, and rotating roller 158, may be substituted therefor
without departing from the spirit of the invention. The driven
shafts and motors for driving the shafts are all mounted to a
mounting bracket 176 which is connected to the support beams 46 of
the handler 18. Operation of the slip sheet removal mechanism 25
will be described hereinafter.
[0035] Referring now to FIG. 7 and FIG. 8, a cassette 24 for
loading into the plate handler is shown. The cassette has a
removable cover 180, which is removed and replaced in a vertical
direction relative to a rectangular bottom container 182 as
indicated by arrows. The bottom container 182 comprises a base
plate 184 surrounded by four aluminum side extrusions 186. The
extrusions 186 are attached at the four 90 degree corners by spring
clips and adhesive (not shown). The base plate 184 is contained
within a slot 188 in the edge of each extrusion 186 and is held in
place with an adhesive on the top side 190 of the base plate 184
and a piece of continuous round flexible urethane belting 192 on
the bottom side of the base plate 184. The round belting 192 is
retained in a thin groove 194 provided in the extrusion 186.
[0036] Three channels 196 (one shown) are fastened to the bottom
side of the base plate 184. The channels 196 act as reinforcing
stiffeners for the bottom container 182, and also are housings for
three locator bars 198. Each locator bar 198 is attached within a
channel 196 by an adhesive. An adjustable stop 200 is provided on
each locator bar 198 to slide along the locator bar and be fastened
to a set position by a lock screw 202 which screws into holes 204
drilled into the locator bars 198. The three adjustable stops 200
locate and secure a stack of plates 26 against several reference
blocks 206 fastened to the side extrusions 186. The adjustable
stops 200 allow multiple sizes of plates 26 to be held against the
reference blocks 206 within a single bottom container 182. The base
plate 184 is provided with embossed areas 208 for the reference
blocks 206 to be set within, which prevents the plates referenced
against the reference blocks 206 from sliding between the reference
block 206 and the base plate 184 and maintaining alignment of the
plates with respect to the reference block 206.
[0037] The cover 180 comprises a top plate 210 and four side
extrusions 212 surrounding the top plate 210. The extrusions 212
are fastened together at the four corners of the top plate 210 by
spring clips and adhesive (not shown). The top plate is secured to
a ledge portion 214 of the extrusions 212 by an adhesive. Two of
the four side extrusions have a handle portion 216 formed in the
extrusion 212 which cooperate with hooks on the undersides of the
cassette tables in the handler to remove and replace the cassette
cover (to be described hereinafter). The inside of the top plate
210 has a layer of foam 218 attached, to ensure that the plates on
the top of a full stack of plates 26 do not slide over the tops of
the reference blocks 206 during loading of a cassette 24 into the
handler 18. The cover 180 and the bottom container 182 are
constructed from light proof materials, so that when the plates are
enclosed within a covered cassette, there is no exposure of the
light sensitive plate contained within the cassette. The attachment
area between the bottom extrusions 186 and the cover extrusions 212
has magnetic strips 220 which ensure the cover 180 is attached
securely to the bottom container 182 and that no light will enter
the cassette 24 during handling.
[0038] The side extrusions 186 are provided with a beveled portion
230 which aid in the loading of the cassette 24 into the plate
handler 18. The handler 18 has a loading platform 232 shown in FIG.
2, extending horizontally from the vertical beams 46 of the
handler. The loading platform 232 has rows of grooved wheels 234
mounted for rotation within the loading platform 232. The grooved
wheels 234 cooperate with the beveled portion 230 of the side
extrusions 186 of the cassette 24 during loading and serve to
register the cassettes in a reference position within the handler.
All tables 34 and 36 within the handler are also provided with the
rows of grooved wheels to facilitate smooth and easy loading of the
cassette from the loading platform onto the support tables in the
handler, while maintaining the cassette in register. The beveled
portions 230 cooperate with the V-grooved surface 236 of the
grooved wheels 234 on opposite outer sides of the cassette 24 for
proper alignment. The cassette is designed to align the plates
inside the cassette against the reference blocks provided on the
interior of the cassette, and also register the cassette into a
reference position within the handler, as shown in FIG. 5,
regardless of the plate size contained in the cassette. The
parallel rails 92 in the handler are fixed relative to the wheels
of the selected table in the access position. This ensures the
registration of the plates within the cassette relative to the
rails 92, and the registration is transferred to the complementary
rails 90 in the engine compartment, and thereby the plate is
delivered in register into the engine from the handler.
[0039] Additional locator stops 238 are provided on each table to
assist in registering the cassette 24 in the loading direction so
that the cassette 24 is pushed into the handler 18 along the
grooved wheels 234 of the table 36, but only to a predetermined
location so that the cassette 24 is registered with respect to two
dimensions and to the picker rails 92. These additional locator
stops 238 are spring loaded and are located between the grooved
wheels 234 within each row of grooved wheels on a table 36. The
stops 238 contact an underside 240 of the side extrusions 186 while
the cassette 24 is being loaded, and when the stop 238 comes into
contact with a recess (not shown) formed in the underside of the
extrusion, the spring force behind the stop 238 forces the stop
into the recess and locks the cassette 24 into a predetermined
position on the table. The wheels 234 register the cassette with
respect to the two reference blocks 206 on one side of the
cassette, while the locator stops 238 within the rows of the wheels
234 register the cassette 24 with respect to the third, alone
reference block 206 on the neighboring side of the cassette. Then
the plates are registered in a known location relative to the
picker, as depicted in FIG. 5.
[0040] The loading platform 232 can be incorporated into the design
of the doors and covers for enclosing the handler in a light tight
environment. The loading platform can function both as a door into
the cassette loading area, and as the loading platform. This is
accomplished by providing an attachment hinge on the handler frame
for the loading platform 232 to pivot between the two functional
positions. The loading platform 232 is pivoted up for a closed door
position, and down and horizontally as shown in FIG. 2 for an open,
cassette loading position.
[0041] Cassettes loaded into the handler house the plates. At any
one time, a cassette holds only like plates (same type, gauge,
size, etc.). Typically, there is a maximum of 50 plates of 0.012''
gauge, 75 plates of 0.008'' gauge, or 100 plates of 0.006'' gauge,
in a single cassette. There are several distinct cassette sizes. A
cassette of a specific size holds a range of plate sizes inside,
however only one size plate is loaded into a cassette at any one
time. Fillers or guides are used to take-up the space between plate
and cassette boundaries. The reference position of the plates
within the cassette is described above with reference to FIG. 5.
Packaging of plates within a cassette is related to both handler
operation and cassette transportability. There may be a mix of
cassettes in the handler (two, three or four cassettes). All
cassettes can be different from each other, in that each houses a
distinct set of plate characteristics (type, size, gauge, etc.)
There may be instances where some or all cassettes inside the
handler have the same plate characteristics.
[0042] Now, with reference to all the Figures, the method for using
the plate handler 18 and picker 28 will be described. The primary
function of the handler 18 is to position a required plate on
demand in an access position for the picker 28, which picks and
delivers the required plate to the engine 20. Once the handler 18
receives a request from the engine 20 for a specific plate, the
following actions take place in the handler, in cooperation with
the engine 20. The picker 28 begins in the home position within the
engine 20. The slip sheet removal mechanism 25 is positioned with
the suction tubes 144, fingers 150, and nip wheels 154 retracted
(as shown in dotted lines for the suction tubes and nip wheels in
FIG. 6) to clear the path of the tables 34, 36 for repositioning by
the elevator mechanism 40. The elevator mechanism 40 moves the
brace 38, lower table 36, and upper tables 34 supported thereon, if
any, to a cover removal/replacement position. In the cover
removal/replacement position, the selected table 36 is located
directly below the table 34 supported by the support bars 56 of the
table support mechanism 44. Hooks on the bottom of the supported
table 34 engage the cover 180 of the selected cassette 24 for
either removal or replacement, so that the cover 180 is separated
from or rejoined with the selected cassette 24.
[0043] In FIG. 2, the cover removal/replacement position for the
lower table 36 is at a position where the open cassette 24 on the
lower table 36 contacts the cover 180 supported by the table 34
immediately above the lower table 36 held by the support bars 56.
When the selected cassette 36 is in the cover removal/replacement
position, the upper tables 34 are all then supported by the brace
38. Then the support bars 56 and shafts 52 are turned 90 degrees by
means of the linkage 60 and drive motor 64. Once the support bars
56 are retracted from the path of motion of the tables 34, 36, the
elevator mechanism 40 moves to the cover removal/replacement
position for the next selected table and cassette. The table
support mechanism 44 moves the support bars 56 into the supporting
position underneath the table directly above the selected cassette
24. The elevator mechanism 40 then moves the selected table down
thereby separating the cover 180 of the selected cassette 24 from
the selected cassette 24 so that the picker can access the plates
26 contained within the cassette 24.
[0044] The picker 28 is then moved from the home position in the
engine 20 into the handler 18 along the rails 90 and 92. Depending
on the size of the plate in the selected cassette 24 the picker 28
adjusts the third row 110 of suction cups relative to the middle
row 108 of suction cups to accommodate for various plate sizes, if
necessary (FIG. 5). The elevator mechanism 40 moves the selected
cassette 24 and plates therein upward to come into contact with the
suction cups 114 on the picker 28 (FIGS. 4 and 6). The suction cups
114 retract into the spring loaded fittings 116 to accommodate for
variations in the stack height of the plates 26 in the cassettes
24, as the elevator 40 moves the cassette 24 up to the picking
position which is at a set vertical height relative to the picker
rails 90, 92. Therefore for a maximum stack height of a full stack
of plates, the suction cups 114 compress against the spring loaded
fittings 116 and retract a length into the fittings, and for a
depleted stack of plates, the suction cups 114 compress against the
spring loaded fittings and retract substantially the same length
minus the height of the stack depletion. The spring loaded fittings
116 also ensure that the plate and the suction cups 114 make
contact to secure the plate onto the picker 28. After the plate is
attached to the picker 28 by the vacuum suction, the first row 106
of suction cups on the picker 28 is pivoted upward, peeling back
the edge of the plate 142 and creating a gap between the plate 142
and the slip sheet 140 underneath.
[0045] The slip sheet removal mechanism 25 activates the peeler air
flow 148, and the fingers 150 are pivoted into position to hold
down the edge of the slip sheet 140 while the elevator mechanism 40
lowers the cassette 24 to a slip sheet removal position. The peeler
air blast 148 remains on while the cassette 24 moves downward to
separate the slip sheet 140 from the bottom of the plate 142 being
picked by the picker 28, which may stick to the plate due to
electrostatic charge. The fingers 150 are pivoted away from the
slip sheet 140 and the suction tubes 144 are pivoted into position
above the slip sheet edge. The suction cups on the ends of the
suction tubes are compliant and flexible so that when the vacuum is
applied and contact is made between a suction cup and the slip
sheet, the slip sheet material is drawn into the suction cup and
the separation of the slip sheet from the plate below it is
initiated. The compliant suction cup deforms to break the slip
sheet away from the lower plate as typically an attractive force
exists between the slip sheet and the plate. This is also an
important step in the process of removing the slip sheet because
the slip sheet may be a porous material and the vacuum applied
through the suction tubes can pass through the slip sheet material
and be applied to the plate below, which is undesirable when
attempting to remove the slip sheet. The selected cassette 24 is
elevated to bring the slip sheet 140 into contact with the suction
tubes 144 while the vacuum is on. The suction tubes 144 pivot
upward slightly to break the adhesion of the slip sheet 140 to the
plate below. The elevator 40 then moves the selected cassette 24
downward from the slip sheet removal mechanism 25 and the suction
tubes 144 pivot back downward to the roller 158 with the slip sheet
140 attached. The vacuum for the suction tubes 144 is turned off
and the slip sheet 140 is released to the rotating roller 158 to
pull the slip sheet 140 away from the stack. The nip wheels 154
pivot from the position shown in solid lines to the position shown
in dotted lines to cooperate with the roller 158 and remove the
slip sheet 140. A sensor 902 indicates that the removal of the slip
sheet 140 is completed and the rotating roller 158 is then halted.
Meanwhile the picker 28 lowers the first row 106 of suction cups
from the peeling position, and the picker 28 travels back into the
engine 20 to the home position. For the next plate to be selected
by the picker 28, the steps are partially repeated if the same
cassette 24 is being picked from, or the steps are repeated from
the beginning of the sequence for another cassette.
[0046] In order to load cassettes into the handler, the following
method steps occur in conjunction with the plate handler apparatus
and the workflow software as described previously. The handler has
sensors positioned appropriately (not shown) to monitor the level
of the plates contained in each cassette. Additionally the handler
has the capability of knowing the types of plates available so that
when a plate needed by the engine is not available, or upon a
sensor detecting an empty cassette, a signal is communicated to the
engine and the operator is alerted through the operator control
terminal 30.
[0047] The picker 28 is returned (if not already there) to begin in
the home position within the engine 20. The slip sheet removal
mechanism 25 is positioned with the suction tubes 144, fingers 150,
and nip wheels 154 retracted (as shown in dotted lines for the
suction tubes and nip wheels in FIG. 6) to clear the path of the
tables 34, 36 for repositioning by the elevator mechanism 40. The
elevator mechanism 40 moves the brace 38, lower table 36, and upper
tables 34 supported thereon, if any, to the cover
removal/replacement position previously described. Then the support
bars 56 and shafts 52 are turned 90 degrees by means of the linkage
60 and drive motor 64. Once the support bars 56 are retracted from
the path of motion of the tables 34, 36, the elevator mechanism 40
moves to the cassette loading position for the selected table and
cassette needing replacement. The cassette loading position is
located where the selected table is adjacent to the loading
platform 232 shown in FIG. 2 extending out from the handler 18 to
support the cassette 24 to slide horizontally between the selected
table and the loading platform 232 during loading and unloading.
Covers and doors (not shown) are provided to enclose the entire
handler frame to maintain the cassette in a light tight
environment. The doors are provided to access the interior of the
handler and at this time the door locks are released to allow
operator access. Then the empty cassette is removed by sliding the
cassette out horizontally along the path formed by the grooved
wheels in the selected table and the loading platform, and then the
cassette is either reloaded or replaced with another cassette. The
cassette presence is monitored by sensors. After detecting the
cassette on the selected table, the handler waits for the doors to
be closed and then the door locks are activated. The elevator moves
up to the cover removal/replacement position for the selected
cassette and normal operation is resumed.
[0048] It will be understood that the preferred embodiment of the
system described herein being a platesetter for imaging aluminum
plates, can be used also with polyester plates, can be modified to
perform as a proofing device rather than a platesetter, such as in
commonly owned, U.S. Pat. No. 5,699,099, entitled "Electronic
Prepress System With Multi-Function Thermal Imaging Apparatus,"
hereby incorporated by reference. Additionally the apparatus
described herein is applicable to production of thermally recorded
printing plates as well as photosensitive lithographic printing
plates recorded by light exposure, with various modification to the
system's processing and imaging components, as appreciated by those
familiar with the art.
[0049] While this invention has been described in terms of various
preferred embodiments, those skilled in the art will appreciate
that various modifications, substitutions, omissions and changes
may be made without departing from the spirit thereof. Accordingly,
it is intended that the scope of the present invention be limited
solely by the scope of the following claims, including equivalents
thereof.
* * * * *