Apparatus and method for picking a single printing plate from a stack of printing plates

Information

  • Patent Grant
  • 6675712
  • Patent Number
    6,675,712
  • Date Filed
    Friday, April 5, 2002
    22 years ago
  • Date Issued
    Tuesday, January 13, 2004
    21 years ago
Abstract
An apparatus and method for picking a single printing plate from a stack of printing plates. The apparatus includes a plurality of suction cups, a peeler, a drive system for displacing the suction cups and the peeler against the surface of the top printing plate on the stack, a vacuum source for supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate, and a system for rotatably displacing the suction cups relative to the peeler to peel a portion of the top printing plate off of the stack. The center line of rotation of the displacing system is located at a contact point between the peeler and the surface of the top printing plate. This prevents any relative motion of the top printing plate against the next, underlying printing plate on the stack during the peeling operation.
Description




FIELD OF THE INVENTION




The present invention is in the field of imaging systems. More particularly, the present invention provides an apparatus and method for picking a single printing plate from a stack of printing plates.




BACKGROUND OF THE INVENTION




In external drum imaging systems, a movable optical carriage is commonly used to displace an image recording source in a slow scan direction while a cylindrical drum, having recording media mounted on an external surface thereof, is rotated with respect to the image recording source. The drum rotation causes the recording media to advance past the image recording source along a fast scan direction that is substantially perpendicular to the slow scan direction.




The image recording source may include an optical system for generating one or more imaging beams that are scanned across the surface of the recording media. Each imaging beam may be separately modulated according to a digital information signal representing data corresponding to the image to be recorded.




The recording media to be imaged by an external drum imaging system is commonly supplied in discrete, flexible sheets, hereinafter collectively referred to as “printing plates.” Each printing plate may comprise one or more layers supported by a support substrate, which for many printing plates is a plano-graphic aluminum sheet. Other layers may include one or more image recording (i.e., “imageable”) layers such as a photosensitive, radiation sensitive, or thermally sensitive layer, or other chemically or physically alterable layers. Printing plates that are supported by a polyester support substrate are also known and can be used in the present invention. Printing plates are available in a wide variety of sizes, typically ranging, e.g., from 9″×12″, or smaller, to 58″×80″, or larger.




A cassette is often used to supply a plurality of unexposed printing plates to an external drum imaging system. The printing plates are normally supplied in stacks of ten to one hundred, depending upon plate thickness and other factors, and are stored in the cassette. Interleaf sheets, commonly referred to as “slip sheets,” may be positioned between the printing plates to protect the emulsion side of the printing plates from physical damage (e.g., scratches), which could render a printing plate unusable for subsequent printing. When Interleaf sheets are not used, great care must be taken to avoid emulsion damage as each printing plate is separated from the stack, fed from the cassette into the external drum imaging system, and mounted on the external drum. Unfortunately, preventing such damage as the printing plates are unloaded and fed from a cassette to an external drum has proven to be a very difficult and expensive task in currently available external drum imaging systems, especially when larger (e.g., 45″ wide) printing plates are used.




SUMMARY OF THE INVENTION




The present invention provides an apparatus and method for picking a single printing plate from a stack of printing plates in an imaging system.




Generally, the present invention provides an apparatus, comprising:




a plurality of suction cups, a peeler, and a system for rotatably displacing the suction cups relative to the peeler, wherein a center line of rotation of the displacing system is located on a surface of the peeler.




The present invention also provides an apparatus for picking a printing plate from a stack of printing plates, comprising:




a plurality of suction cups, a peeler, a drive system for displacing the suction cups and the peeler against a surface of a top printing plate on the stack, a vacuum source for supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate, and a system for rotatably displacing the suction cups relative to the peeler to peel a portion of the top printing plate off of the stack, wherein a center line of rotation of the displacing system is located at a contact point between the peeler and the surface of the top printing plate.




The present invention further provides a method for picking a printing plate from a stack of printing plates, comprising:




displacing a plurality of suction cups and a peeler against a surface of a top printing plate on the stack;




supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate; and




rotatably displacing the suction cups relative to the peeler to peel a portion of the top printing plate off of the stack, wherein a center line of rotation of the displacement is located at a contact point between the peeler and the surface of the top printing plate.




The present invention also provides a method for picking a printing plate from a stack of printing plates, comprising:




displacing a plurality of suction cups and a peeler against a surface of a top printing plate on the stack;




supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate; and




peeling a portion of the top printing plate off of the stack, and preventing relative motion of the top printing plate against an underlying printing plate on the stack, by rotatably displacing the suction cups relative to the peeler, wherein a center line of rotation of the displacement is located at a contact point between the peeler and the surface of the top printing plate.











BRIEF DESCRIPTION OF THE DRAWINGS




The features of the present invention will best be understood from a detailed description of the invention and embodiments thereof selected for the purpose of illustration and shown in the accompanying drawings in which:





FIG. 1

illustrates an external drum imaging system for recording images onto a printing plate.





FIG. 2

illustrates an example of an imaging system including a movable optical carriage and scanning system, usable in the external drum imaging system of FIG.


1


.





FIG. 3

is an end view of an external drum platesetter including a cassette, a printing plate picking system in accordance with the present invention, and a printing plate supporting and feeding system.





FIGS. 4-8

illustrate the operation of the external drum platesetter of FIG.


3


.





FIG. 9

illustrates the printing plate supporting and A feeding system.





FIGS. 10-16

illustrate the structure and operation of the printing plate picking system of the present invention.





FIGS. 17-18

illustrate a lip segment of an exemplary plate rest.











DETAILED DESCRIPTION OF THE INVENTION




The features of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings. Although the drawings are intended to illustrate the present invention, the drawings are not necessarily drawn to scale.




An example of an external drum imaging system


10


is illustrated in FIG.


1


. In this example, the imaging system


10


comprises an external drum platesetter configured to record digital data onto a printing plate


18


. Although described below with regard to an external drum platesetter, the plate picking system of the present invention may be used in conjunction with a wide variety of other types of external drum, internal drum, or flatbed imaging systems, including imagesetters and the like, without departing from the intended scope of the present invention.




The imaging system


10


generally includes a front end computer or workstation


12


for the design, layout, editing, and/or processing of digital files representing pages to be printed, a raster image processor (RIP)


14


for processing the digital pages to provide rasterized page data (e.g., rasterized digital files) for driving an image recorder, and an image recorder or engine, such as an external drum platesetter


16


, for recording the rasterized digital files onto a printing plate


18


.




A stack


20


of printing plates


18


is commonly supplied in a cassette


22


. A printing plate


18


is picked off of the stack


20


and subsequently mounted on an external drum


24


of the external drum platesetter


16


by an autoloading system


26


. The printing plates


18


on the stack


20


are arranged one on top of the other without the use of protective slip sheets.




The external drum platesetter


16


includes an external drum


24


having a cylindrical media support surface


30


for supporting a printing plate


18


during imaging. The external drum platesetter


16


further includes a scanning system


32


, coupled to a movable carriage


34


, for recording digital data onto the imaging surface


36


of the printing plate


18


using a single or multiple imaging beams


38


. An example of a scanning system


32


is illustrated in FIG.


2


. In particular, the scanning system


32


is displaced by the movable carriage


34


in a slow scan axial direction (directional arrow A) along the length of the rotating external drum


24


to expose the printing plate


18


in a line-wise manner when a single beam is used or in a section-wise manner for multiple beams. Other types of imaging systems may also be used in the present invention.




The external drum


24


is rotated by a drive system


40


in a clockwise or counterclockwise direction as indicated by directional arrow B in FIG.


1


. Typically, the drive system


40


rotates the external drum


24


at a rate of about 100-1000 rpm. As further illustrated in

FIG. 2

, the scanning system


32


includes a system


42


for generating the imaging beam or beams


38


. The system


42


comprises a light or radiation source


44


for producing the imaging beam or beams


38


(illustrated for simplicity as a single beam), and an optical system


46


positioned between the radiation source


44


and the media support surface


30


for focusing the imaging beam or beams


38


onto the printing plate


18


. It should be noted, however, that the system


42


described above is only one of many possible different types of scanning systems that may be used to record image data on the printing plate


18


.




In the external drum imaging system


10


shown in

FIG. 1

, the leading edge


48


of the printing plate


18


is held in position against the media support surface


30


of the external drum


24


by a leading edge clamping mechanism


50


. Similarly, the trailing edge


52


of the printing plate


18


is held in position against the media support surface


30


of the external drum


24


by a trailing edge clamping mechanism


54


. The leading edge clamping mechanism


50


and the trailing edge clamping mechanism


54


both provide a tangential friction force between the printing plate


18


and the media support surface


30


of the external drum


24


that is sufficient to resist the tendency of the edges of the printing plate


18


to pull out of the clamping mechanisms


50


,


54


, at a high drum rotational speed. Other known systems for mounting the printing plate


18


onto the external drum


24


may also be used.




A vacuum source


56


may be used to draw a vacuum through an arrangement of ports and vacuum grooves


58


(

FIG. 2

) to hold the printing plate


18


against the media support surface


30


of the external drum


24


. The vacuum source


56


may also supply a vacuum to a plate picking system that is configured to remove or “pick” the top printing plate


18


from the stack


20


of printing plates. A registration system (not shown), comprising, for example, a set of registration pins on the external drum


24


, and a plate edge detection system (not shown), may be used to accurately and repeatably position and locate each printing plate


18


on the external drum


24


.




The basic structure of an external drum platesetter


16


, which includes a plate picking system


100


for picking a single printing plate


18


from a stack


20


of printing plates


18


in accordance with the present invention, is illustrated in FIG.


3


. In this example, the stack


20


of printing plates


18


are provided in a cassette


102


having a printing plate supporting and feeding system


104


. The external drum platesetter


16


includes an external drum


24


having a cylindrical media support surface


30


for supporting a printing plate


18


during imaging. The external drum


24


is supported by a frame


106


. A drive system


40


rotates the external drum


24


during imaging. A scanning system


32


, carried by a movable carriage


34


, travels axially along the rotating external drum


24


to record digital data onto the imaging surface of a printing plate mounted on the external drum


24


. The external drum


24


and scanning system


32


are positioned on a base


108


.




The cassette


102


contains a stack


20


of printing plates


18


(e.g., twenty-five printing plates). Only four printing plates


181


,


182


,


183


,


184


, are illustrated in

FIG. 3

for clarity. Protective slip sheets are not present between the individual printing plates


18


of the stack


20


. The printing plates


18


are manually loaded and stacked within the cassette


102


, which is intended to be reusable. Alternately, the printing plates


18


may be automatically loaded into the cassette


102


using any suitable loading mechanism. The printing plates


18


are stacked with their emulsion sides facing toward the plate picking system The printing plate supporting and feeding system


104


is located within the cassette


102


, and generally comprises a plurality of plate feed beams


110


that are attached to, and extend between, a pair of endless, rotatable timing belts


112


(only one is shown in FIG.


3


). The stack


20


of printing plates


18


is located between the pair of timing belts


112


. The plate feed beams


110


are configured to support large printing plates


18


without the need for a center support. The profile of each plate feed beam


110


is designed with a high stiffness to weight ratio such that, when supporting a printing plate


18


in the manner described below with regard to

FIGS. 6 and 7

, the plate feed beams


110


will not deflect and contact the underlying stack


20


of printing plates


18


. In an alternate embodiment of the present invention, the stack


20


of printing plates


18


, as well as the printing plate supporting and feeding system


104


, are not enclosed within a cassette.




The timing belts


112


transfer the rotary motion of a drive system


114


, such as an electric motor, to a linear motion of the plate feed beams


110


. A guide roller (not shown) is positioned at the opposing side of each timing belt


112


to allow rotation of the timing belt. A controller (not shown) is used to accurately control the drive system


114


and resultant displacement of the timing belts


112


and plate feed beams


110


in a manner known in the art. As presented in greater detail below, the linear motion of the plate feed beams


110


operates to peel the top printing plate


18


, off of the stack


20


of printing plates, allowing the top printing plate


18


, to be subsequently loaded and mounted onto the media support surface


30


of the external drum


24


.




The plate picker system


100


of the present invention is used to pick up a bottom edge of the top printing plate


18




1


from the stack


20


. The plate picker system


100


generally comprises a plurality of suction cups


116


(only one is shown) arranged parallel to the bottom edge of the printing plates


18


on the stack


20


, a system


118


for displacing the suction cups


116


relative to the top printing plate


18




1


, and a vacuum source


56


for supplying a vacuum to the suction cups


116


.




The general operation of the plate picking system


100


of the present invention, and the printing plate supporting and feeding system


104


, is illustrated in

FIGS. 4-8

. The plate picking system


100


will be described in greater detail below with reference to

FIGS. 10-16

.




In

FIG. 4

, with the plate feed beams


110


in a “home” position within the cassette


102


, the suction cups


116


of the plate picking system


100


are moved by the displacing system


118


into contact with a bottom edge of the top printing plate


18




1


on the stack


20


. The suction cups


116


are moved toward and against the bottom edge of the top printing plate


18




1


as indicated by directional arrow


120


. A vacuum is applied to the suction cups


116


by the vacuum source, thereby securely coupling the bottom edge of the top printing plate


18




1


to the displacing system


118


.




In

FIG. 5

, the bottom edge of the top printing plate


18




1


is peeled away from the stack


20


of printing plates as the displacing system


118


moves the suction cups


116


away from the stack


20


as indicated by directional arrow


122


. The top printing plate


18




1


is displaced in direction


122


until the bottom edge of the top printing plate


18




1


is positioned outside the periphery of the timing belts


112


. The bottom edge of the top printing plate


18


, is held in this position by the displacing system


118


.




At this point in the operation of the printing plate supporting and feeding system


104


, as illustrated in

FIG. 6

, the drive system


114


rotates the timing belts


112


in the direction indicated by directional arrow


124


. This results in a corresponding displacement of the attached plate feed beams


110


. As the leading plate feed beams


110


pass under the bottom edge of the top printing plate


18




1


that is coupled to, and held stationary by, the displacing system


118


, the plate feed beams


110


engage and slide against the underside of the top printing plate


181


, effectively peeling the top printing plate


18




1


away from, and partially off of, the next printing plate


182


on the stack


20


. As shown in

FIG. 7

, rotation of the timing belts


112


continues in direction


124


until the top printing plate


18




1


is fully peeled off of the stack


20


and is supported by the plate feed beams


110


. At this point, with the printing plate supporting and feeding system


104


in a “plate loaded” position within the cassette


102


, the top printing plate


18




1


no longer contacts the next printing plate


182


on the stack


20


. During the “peeling” operation, the plate feed beams


110


do not contact the top surface (i.e., the emulsion side) of the next printing plate


18




2


on the stack


20


; the plate feed beams


110


only contact and slide against the underside of the top printing plate


18




1


. This prevents the emulsion side of the next printing plate


18




2


from being damaged.




The displacing system


118


(and attached top printing plate


18




1


) is shifted downward as indicated by directional arrow


126


to position the bottom edge of the top printing plate


18




1


above the nip rollers


128


. The vacuum supplied by the vacuum source to the suction cups


116


is then released, and the suction cups


116


are displaced away from the top printing plate


18




1


as indicated by directional arrow


130


. Guide means may be provided within the cassette


102


to direct the bottom edge of the top printing plate


18




1


between the pair of nip rollers


128


.




The nip rollers


128


, which may be formed as part of the cassette


102


or other suitable portion of the external drum platesetter


16


, operate to direct the bottom (i.e., leading) edge of the top printing plate


18




1


to a plate mounting system (not shown) that is configured to mount the printing plate onto the external drum


24


of the external drum platesetter


16


for subsequent imaging. The top printing plate


18




1


is shown mounted to the external drum


24


in FIG.


8


. Such a mounting system is disclosed in detail, for example, in U.S. Pat. No. 6,295,929, entitled “External Drum Imaging System,” which is incorporated herein by reference.




As illustrated in

FIG. 8

, after the printing plate


18




1


exits the cassette


102


, the drive system


110


reverses the direction of rotation of the timing belts


112


, thereby rotating the timing belts


112


in the direction indicated by directional arrow


132


. The rotation of the timing belts


112


, and the corresponding displacement of the plate feed beams


110


, continues until the plate feed beams


110


are returned to their “home” position within the cassette


102


. The next printing plate


18




2


on the stack


20


, which now assumes the role of the “top” printing plate, can be fed from the cassette


102


to the external drum


24


by repeating the steps described above with regard to

FIGS. 3-8

.




The printing plate supporting and feeding system


104


of the present invention is illustrated in greater detail in FIG.


9


. As shown, the printing plate supporting and feeding system


104


comprises a pair of timing belts


112


and a plurality of plate feed beams


110


attached to, and extending between, the timing belts


112


. Each plate feed beam


110


includes a series of rotatable rollers


134


that allow a printing plate


18


and the plate feed beam


110


to slide across each other with minimal resistance.




The structure and operation of the plate picking system


100


of the present invention is illustrated in detail in

FIGS. 10-16

.




The plate picking system


100


of the present invention is illustrated in its home position adjacent the nip rollers


128


in FIG.


10


. The plate picking system


100


includes a plurality of vacuum cups


116


(only one is shown) that are coupled to a vacuum manifold


140


. A vacuum source


56


(

FIG. 1

) selectively supplies a vacuum to the plurality of suction cups


116


through the vacuum manifold


140


. The vacuum cups


116


extend across at least a portion of the width of the stack


20


of printing plates


18


stored in the cassette


22


. Only three printing plates


18




1


,


18




2


,


18




3


, are illustrated in

FIG. 10

for clarity The vacuum manifold is mounted to the end of a movable, angled bar


142


. The angled bar


142


is secured to a pin


144


that is rotatably coupled to a drive system. In this embodiment, the drive system comprises a pneumatic cylinder


150


, wherein the pin


144


is rotatably coupled to the end


146


of the piston


148


of the pneumatic cylinder


150


. The pneumatic cylinder


150


is rotatably coupled to a pin


152


that is secured to a movable platform


154


.




A curved slot


156


that comprises a segment of a circle is formed in the movable platform


154


. A pair of wheels


158


, which are attached to the underside of the angled bar


142


by axles


160


, are positioned within the curved slot


156


. The angled bar


142


is located above the movable platform


154


. The pair of wheels


158


extend below the angled bar


142


into the curved slot


156


.




An arc-shaped peeler


162


is positioned adjacent the vacuum cups


116


. The arc-shaped peeler


162


extends across at least a portion of the width of the stack


20


of printing plates


18


stored in the cassette


22


. A support


164


is mounted to each end of the arc-shaped peeler


162


. A first drive system


166


is provided for displacing the peeler


162


and the movable platform


154


in unison toward and away from the stack


20


as indicated by directional arrow


168


. The first drive system


166


may comprise any suitable type of linear drive system including a pneumatic cylinder, a motor driven belt/chain system, etc.




A second drive system


170


is provided for displacing the peeler


162


, the movable platform


154


, and the first drive system


166


in unison between the nip rollers


128


and the stack


20


of printing plates


18


in the cassette


22


as indicated by directional arrow


172


. The second drive system


170


may also comprise any suitable type of linear drive system including a pneumatic cylinder, a motor driven belt/chain system, etc.




As shown in

FIG. 11

, the peeler


162


, the movable platform


154


, and the first drive system


166


are displaced by the second drive system


170


as indicated by directional arrow


174


to position the peeler


162


and the vacuum cups


116


adjacent the bottom edge of the top printing plate


18




1


on the stack


20


. The piston


148


of the pneumatic cylinder


150


is extended during or after the displacement. This results in a displacement of the wheels


158


of the angled bar


142


within the curved slot


156


as indicated by directional arrow


176


. The curvature of the slot


156


causes the pin


144


and the angled bar


142


to rotate clockwise as indicated by directional arrow


178


, thereby positioning the vacuum cups


116


even with the peeler


162


and normal to the surface of the top printing plate


18




1


on the stack


20


. The centerline (CL) of rotation of the angled bar


142


within the curved slot


156


is located at the mid-point of the surface


180


of the peeler


162


. Thereafter, as illustrated in

FIG. 12

, the first drive system


166


displaces the peeler


162


and the suction cups


116


as indicated by directional arrow


180


to position the peeler


162


and the suction cups


116


against the bottom edge of the top printing plate


18




1


. A vacuum is subsequently supplied to the suction cups


116


through the vacuum manifold


140


to secure the suction cups


116


to the bottom edge of the top printing plate


18




1


.




Once the top printing plate


18




1


has been secured by the suction cups


116


, the piston


148


of the pneumatic cylinder


150


is retracted as illustrated in FIG.


13


. This results in a displacement of the wheels


158


of the angled bar


142


within the curved slot


156


as indicated by directional arrow


18




2


. The curvature of the slot


156


causes the pin


144


and the angled bar


142


to rotate counter-clockwise as indicated by directional arrow


184


, thereby peeling the bottom edge of the top printing plate


18




1


off of the stack


20


. The centerline (CL) of rotation of the angled bar


142


within the curved slot


156


is located on the surface of the top printing plate


18




1


at the mid-point (i.e., the contact point) of the surface


180


of the peeler


162


. This ensures that as the top printing plate


18




1


is peeled from the stack


20


, there is no relative motion (e.g., rubbing) of the top printing plate


18




1


against the next, underlying printing plate


18




2


on the stack


20


. The top printing plate


18




1


, therefore, does not rub or otherwise damage the delicate emulsion surface of the next printing plate


18




2


.




The cassette


22


includes a lip


186


that acts as a plate rest. The lip


186


has a friction surface


188


that, along with the peeling motion of the bottom edge of the top printing plate


18




1


, ensures that only one printing plate


18


at a time is picked off of the stack


20


. The lip


186


may be formed as a single unit, or using a plurality of lip segments that are spaced apart along the bottom edge of the cassette


22


. An exemplary embodiment of such a lip segment


194


is illustrated in

FIGS. 17 and 18

. In particular, the lip segment


194


includes a friction surface


188


that is formed using a plurality of serrated teeth


196


. The serrated teeth


196


are configured to rub against the bottom of a printing plate


18


as the printing plate


18


is peeled off of the stack


20


of printing plates


18


in the cassette


22


in direction


198


. As shown in

FIG. 18

, the serrated teeth


196


may be situated on a plane that is oriented at an angle (e.g., 5-9 degrees) with respect to the bottom of the stack of printing plates. Other types of friction surfaces


188


may also be used in the practice of the present invention.




As illustrated in

FIG. 14

, the first drive system


166


displaces the peeler


162


and the suction cups


116


away from the stack


20


as indicated by directional arrow


190


to peel the top printing plate


18




1


further off of the stack


20


. The top printing plate


18




1


is peeled off of the stack


20


a sufficient distance to provide clearance for the plate feed beams


110


of the printing plate supporting and feeding system


104


(FIG.


6


). The top printing plate


18




1


, which now rests on the plate feed beams of the printing plate supporting and feeding system (not shown), is displaced (

FIG. 15

) by the second drive system


170


toward the nip rollers


128


as indicated by directional arrow


192


. Finally, as shown in

FIG. 16

, the piston


148


of the pneumatic cylinder


150


is extended to position the bottom edge of the top printing plate


18




1


above the center of the nip rollers


128


. The input nips


128


direct the top printing plate


18




1


to a plate mounting system (not shown) that is configured to mount the top printing plate


18




1


onto the external drum


24


of the external drum platesetter


16


for subsequent imaging (FIG.


8


). The above process can be repeated to pick and peel each remaining printing plate


18


off of the stack


20


.




The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention.



Claims
  • 1. An apparatus, comprising:a plurality of suction cups; an arc-shaped peeler; and a system for rotatably displacing the suction cups relative to the arc-shaped peeler; wherein a center line of rotation of the displacing system is located at a mid-point of an outer surface of the arc-shaped peeler.
  • 2. The apparatus of claim 1, wherein the displacing system comprises:a platform; an angled bar having a plurality of wheels, wherein the suction cups are coupled to the angled bar; a curved slot formed in the platform, wherein the wheels of the angled bar are located within the curved slot; and a drive system for displacing the angled bar along the curved slot, wherein a displacement of the angled bar results in a rotation of the suction cups relative to the arc-shaped peeler.
  • 3. The apparatus of claim 2, wherein the curved slot comprises a segment of a circle.
  • 4. The apparatus of claim 2, wherein the drive system comprises a pneumatic cylinder.
  • 5. The apparatus of claim 4, further comprising:a pin for rotatably coupling an end of a piston of the pneumatic cylinder to the angled bar.
  • 6. The apparatus of claim 4, further comprising:a pin for rotatably coupling the pneumatic cylinder to the platform.
  • 7. The apparatus of claim 1, further comprising:a stack of printing plates, wherein the suction cups and the peeler contact a surface of a top printing plate on the stack, and wherein the center line of rotation of the displacing system is located at a contact point between the arc-shaped peeler and the surface of the top printing plate.
  • 8. The apparatus of claim 7, further comprising:a vacuum source for providing a vacuum to the suction cups to secure the suction cups to the surface of the top printing plate.
  • 9. The apparatus of claim 7, wherein the displacing system displaces the suction cups away from the stack of printing plates, thereby peeling a portion of the top printing plate off of an underlying printing plate on the stack.
  • 10. An apparatus for picking a printing plate from a stack of printing plates, comprising:a plurality of suction cups; an arc-shaped peeler; a drive system for displacing the suction cups and the arc-shaped peeler against a surface of a top printing plate on the stack; a vacuum source for supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate; and a system for rotatably displacing the suction cups relative to the arc-shaped peeler to peel a portion of the top printing plate off of the stack, wherein a center line of rotation of the displacing system is located at a contact point between the arc-shaped peeler and the surface of the top printing plate.
  • 11. The apparatus of claim by 10, wherein the center line of rotation of the displacing system is located at a mid-point of an outer surface of the arc-shaped peeler.
  • 12. The apparatus of claim 10, wherein the displacing system comprises:a platform; an angled bar having a plurality of wheels, wherein the suction cups are coupled to the angled bar; a curved slot formed in the platform, wherein the wheels of the angled bar are located within the curved slot; and a second drive system for displacing the angled bar along the curved slot, wherein a displacement of the angled bar results in a rotation of the plurality of suction cups relative to the arc-shaped peeler.
  • 13. The apparatus of claim 12, wherein the curved slot comprises a segment of a circle.
  • 14. The apparatus of claim 12, wherein the second drive system comprises a pneumatic cylinder.
  • 15. The apparatus of claim 14, further comprising:a pin for rotatably coupling an end of a piston of the pneumatic cylinder to the angled bar.
  • 16. The apparatus of claim 14, further comprising:a pin for rotatably coupling the pneumatic cylinder to the platform.
  • 17. The apparatus of claim 10, wherein the second drive system displaces the suction cups, the peeler, and the top printing plate that is secured to the suction cups away from the stack.
  • 18. The apparatus of claim 17, further comprising:a displacing system for displacing the top printing plate that is secured to the suction cups toward a pair of nip rollers.
  • 19. The apparatus of claim 10, further comprising:a plate rest for supporting the stack of printing plates, wherein the plate rest includes a friction surface.
  • 20. The apparatus of claim 19, wherein the friction surface comprises a plurality of serrated teeth.
  • 21. The apparatus of claim 20, wherein the serrated teeth are situated on a plane that is oriented at an angle with respect to a bottom of the stack of printing plates.
  • 22. A method for picking a printing plate from a stack of printing plates, comprising:displacing a plurality of suction cups and a peeler against a surface of a top printing plate on the stack; supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate; and rotatably displacing the suction cups relative to the peeler to peel a portion of the top printing plate off of the stack, wherein a center line of rotation of the displacement is located at a contact point between the peeler and the surface of the top printing plate.
  • 23. A method for picking a printing plate from a stack of printing plates, comprising:displacing a plurality of suction cups and a peeler against a surface of a top printing plate on the stack; supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate; and peeling a portion of the top printing plate off of the stack, and preventing relative motion of the top printing plate against an underlying printing plate on the stack, by rotatably displacing the suction cups relative to the peeler, wherein a center line of rotation of the displacement is located at a contact point between the peeler and the surface of the top printing plate.
  • 24. An apparatus, comprising:a plurality of suction cups; a peeler; and a system for rotatably displacing the suction cups relative to the peeler, the displacing system including a platform, an angled bar having a plurality of wheels, wherein the suction cups are coupled to the angled bar, a curved slot formed in the platform, wherein the wheels of the angled bar are located within the curved slot, and a drive system for displacing the angled bar along the curved slot, wherein a displacement of the angled bar results in a rotation of the suction cups relative to the peeler; wherein a center line of rotation of the displacing system is located on a surface of the peeler.
  • 25. The apparatus of claim 24, wherein the peeler is arc-shaped.
  • 26. The apparatus of claim 25, wherein the center line of rotation of the displacing system is located at a mid-point of the surface of the arc-shaped peeler.
  • 27. The apparatus of claim 24, wherein the curved slot comprises a segment of a circle.
  • 28. The apparatus of claim 24, wherein the drive system comprises a pneumatic cylinder.
  • 29. The apparatus of claim 28, further comprising:a pin for rotatably coupling an end of a piston of the pneumatic cylinder to the angled bar.
  • 30. The apparatus of claim 28, further comprising:a pin for rotatably coupling the pneumatic cylinder to the platform.
  • 31. An apparatus for picking a printing plate from a stack of printing plates, comprising:a plurality of suction cups; a peeler; a drive system for displacing the suction cups and the peeler against a surface of a top printing plate on the stack; a vacuum source for supplying a vacuum to the suction cups to secure the suction cups against the surface of the top printing plate; and a system for rotatably displacing the suction cups relative to the peeler to peel a portion of the top printing plate off of the stack, the displacing system including a platform, an angled bar having a plurality of wheels, wherein the suction cups are coupled to the angled bar, a curved slot formed in the platform, wherein the wheels of the angled bar are located within the curved slot, and a second drive system for displacing the angled bar along the curved slot, wherein a displacement of the angled bar results in a rotation of the plurality of suction cups relative to the peeler, wherein a center line of rotation of the displacing system is located at a contact point between the peeler and the surface of the top printing plate.
  • 32. The apparatus of claim 31, wherein the peeler is arc-shaped.
  • 33. The apparatus of claim 32, wherein the center line of rotation of the displacing system is located at a mid-point of the surface of the arc-shaped peeler.
  • 34. The apparatus of claim 31, wherein the curved slot comprises a segment of a circle.
  • 35. The apparatus of claim 31, wherein the second drive system comprises a pneumatic cylinder.
  • 36. The apparatus of claim 35, further comprising:a pin for rotatably coupling an end of a piston of the pneumatic cylinder to the angled bar.
  • 37. The apparatus of claim 35, further comprising:a pin for rotatably coupling the pneumatic cylinder to the platform.
US Referenced Citations (6)
Number Name Date Kind
4155546 Jacobs May 1979 A
4218054 Bauer et al. Aug 1980 A
4218055 Krobel et al. Aug 1980 A
4311304 Hamada et al. Jan 1982 A
4815723 Iizuka Mar 1989 A
5879003 Kovach et al. Mar 1999 A
Foreign Referenced Citations (1)
Number Date Country
3-288737 Dec 1991 JP