Plate registering system and method of operation

Information

  • Patent Grant
  • 6801302
  • Patent Number
    6,801,302
  • Date Filed
    Monday, January 6, 2003
    22 years ago
  • Date Issued
    Tuesday, October 5, 2004
    20 years ago
Abstract
A substrate manager for a substrate exposure machine is used, in one example, as a platesetter. As such, it comprises a substrate storage system, containing one or more stacks of substrates, such as plates in one implementation. A substrate picker is provided for picking substrates from the stack of substrates. The substrates are then handed to a transfer system that conveys the substrates to an imaging engine. A substrate registration system is provided upstream of the imaging engine. The substrate registration system includes (1) a substrate transfer system for supporting and conveying substrates and (2) at least one engaging member for pushing the substrates on the substrate transfer system to a desired position. Preferably, two sets of engaging members are used, one on either side of the plates. This allows angular as well as positional registration. The substrate transfer system includes a frame and a series of rollers for supporting the substrates.
Description




BACKGROUND OF THE INVENTION




Imagesetters and platesetters are used to expose the substrates in many conventional offset printing systems. Imagesetters are typically used to expose the film that is then used to make the plates for the printing system. Platesetters are used to directly expose the plates.




For example, plates are typically large substrates that have been coated with photosensitive or thermally-sensitive material layers, referred to the emulsion. For large run applications, the substrates are fabricated from aluminum, although organic substrates, such as polyester or paper, are also available for smaller runs.




Computer-to-plate printing systems are used to render digitally stored print content onto these printing plates. Typically, a computer system is used to drive an imaging engine of the platesetter. In a common implementation, the plate is fixed to the outside or inside of a drum and then scanned with a modulated laser source in a raster fashion.




The imaging engine selectively exposes the emulsion that is coated on the plates. After this exposure, the emulsion is developed so that during the printing process, inks will selectively adhere to the plate's surface to transfer the ink to print medium.




Automated systems exist for handling the substrates before and after exposure in the imaging engine. These management systems typically pick individual substrates from cassettes and then feed the substrates to the imaging engine. Thereafter, the substrates are unloaded and passed on for further processing.




SUMMARY OF THE INVENTION




The plate must be properly feed into the imaging engine. These are high-resolution devices. They can compensate for some angular and positional misalignment of the plate on the drum, but if the positional or angular misalignment is too large, it can impact the performance of these imaging engines.




The present invention is directed to a substrate registration system for a substrate exposure machine, such as a platesetter or imagesetter. Specifically, it moves the plate or substrate to a known or desired position, so that the plate or substrate can then be properly inserted into the imaging engine and typically installed around its drum. Such registration is critical to the proper handling of plates in these plate management systems.




In general, according to one aspect, the invention features a substrate registering system for a substrate exposure machine. In a typical example, the substrate exposure machine is a platesetter or imagesetter. The substrate registering system comprises a substrate transfer system for supporting and conveying substrates in the substrate exposure machine. At least one engaging member is provided for pushing the substrates on the substrate transfer system to a desired position.




In a current implementation, the substrate transfer system comprises a frame and a series of rollers for supporting the substrates. The rollers are driven to convey the substrates relative to the substrate transfer system in the fashion of a conveyor. Typically, the substrates are moved from a substrate store to the imaging engine.




The engaging members extend typically in a direction that is orthogonal to the plane of the substrate transfer system. The engaging members move in a direction that is perpendicular to a direction in which the substrates are conveyed by the substrate transfer system. In this way, they can push the substrates to the desired position on the substrate transfer system.




In a preferred embodiment, at least one right engaging member and at least one left engaging member are provided to contact opposed sides of the substrates. In this way, they can move the substrates to a desired position, typically in the center of the substrate transfer system. This also allows the substrates to be angularly aligned.




In general, according to another aspect, the invention also features a method for moving plates in a platesetter. This method comprises picking plates from a plate store. The plates are then conveyed to an imaging engine for exposure. Prior to loading the plates in the imaging engine, however, the plates are registered to a desired position.




The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.











BRIEF DESCRIPTION OF THE DRAWINGS




In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings:





FIG. 1

is a schematic, side plan view of a plate manager according to the present invention;





FIG. 2

is a perspective view showing the substrate transfer system and the substrate registration system according to the present invention; and





FIG. 3

is a schematic perspective view showing the inventive substrate registration system.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS





FIG. 1

shows a substrate, and more specifically a plate, manager


20


, which has been instructed according to the principles of the present invention.




Generally, the plate manager


20


comprises a plate store


200


, a plate transfer system


400


, a plate inserter


600


, and a plate imaging engine


500


, all of which are controlled by a system controller


50


.




The plate storage system


200


comprises, when loaded, multiple cassettes


210


. Each of these cassettes


210


holds a stack of plates


212


. The cassettes are moved vertically within the plate store


200


by a cassette elevator or lifter


214


.




In one example, the cassettes themselves are stored in stacks of cassettes and moved vertically by the cassette elevator


214


so that the stack of plates


212


of a specific cassette


210


is raised to the level of a plate picker system


216


. Once the cassette


212


is at the proper height, it is moved laterally. The cassette


212


is thereby positioned underneath the plate picker system


216


, which then picks a plate off of the stack of plates


212


.




The plate picker system


216


provides individual plates from the stack of plates


212


to the plate transfer system


400


. This transfer system


400


currently comprises a conveyer


410


that receives the plate


10


and then moves the plate


10


laterally in the plate manager


20


toward the plate imaging engine


500


.




Between the plate imaging engine


500


and the transfer system


400


is a plate inserter system


600


. The angle of the plate is moved from a generally horizontal orientation as it is received from the transfer system


400


to a more vertical orientation to be compatible for insertion into the plate imaging engine


500


. Specifically, the plate is angled at 75 degrees from horizontal for insertion into the engine.




Specifically, the plate inserter system


600


comprises an inserter arcuate transfer path


610


. It moves the plate from its horizontal position as it is transferred across the conveyer


410


to a more vertical orientation. Specifically, it transfers the plate


10


so that it is received by a first set of output pinch rollers


612


.




The plate imaging engine


500


receives the plate


10


from the plate inserter system


600


. The plate is brought into engagement with a header clip


510


on the exterior of drum


512


of the imaging engine


500


. The drum


512


is then advanced so that the plate


10


is progressively installed on the outside perimeter of the drum


512


by ironing roller


540


until a trailing edge clip


514


engages its trailing edge.




At this stage, the plate


10


is selectively exposed by a laser scanning system


516


. Typically, this is a high speed, high power laser scanning system that selectively exposes the emulsion on the plate


10


with the desired image, in a raster fashion. Afterward, the plate


10


is typically ejected from the plate imaging engine


500


to further machines for development and further processing.





FIG. 2

shows the plate conveyer


410


of the plate transfer system


400


. It comprises a series of rollers


620


. These rollers are supported to rotate on a right frame member


622


and a left frame member


624


. These rollers


620


generally form an upper planar surface on which the plate


10


is supported.




A roller drive belt


628


strung over on a series of conveyor pulleys


626


that are disposed between each of the rollers


620


. As a result, the roller drive belt


628


is urged into engagement with the outer surfaces of the rollers


620


. Thus, when a roller drive motor


630


is driven under the control of the controller


50


, the roller drive belt


628


causes the rollers


620


to rotate in a counter clockwise direction and thereby move or convey the plate


10


in the direction of arrow


11


to the imaging engine


500


.




The inventive substrate registering system comprises a set of engaging members


710


. In the orientation of

FIG. 2

, only the left engaging members


710


-


1


are shown. There is, however, a second set of right engaging members in the preferred embodiment.




Each one of the engaging members


710


comprises a wheel


712


that is held generally at the plane of the substrate


10


. The wheels


712


are oriented to rotate around an axis that is orthogonal to the plane of the conveyer


410


and thus plate


10


. As a result, they can engage the sides of the substrate


10


, even while the conveyer


10


is conveying the plate or substrate


10


in the direction of arrow


11


.




The wheels


712


are supported on respective wheel axles


714


. These, in turn, project upwards from a rack


716


.





FIG. 3

shows the substrate registering system with the conveyer


410


removed and portions of the right and left frame members


622


,


624


cut away. Specifically, there is a set of left engaging members


710


-


1


and a set of right engaging members


710


-


2


. These members, in turn, are supported by a respective left rack


716


and a right rack


730


. The racks


716


and


730


are supported to ride or slide on a front rail


720


and rear rail


718


, which are supported by the right and left frame members


622


,


624


. As a result, the racks


716


and


730


are held in a parallel orientation relative to each other and extend in the direction of plate travel, see arrow


11


.




The racks


716


,


730


are free to slide in the direction of arrows


740


. As a result, when the racks are moved toward each other, the wheels


712


-


1


,


712


-


2


are moved toward each other to thereby engage a plate between the left wheels


712


-


1


and the right wheels


712


-


2


. This movement and engagement causes the plate


10


to be brought into angular alignment and centered in the middle of the conveyor


410


.




In the present embodiment, the left rack


716


and the right rack


730


are moved using a combination of a timing belt


732


, timing belt pulleys


734


,


736


and a rack drive motor


738


. Specifically, the left rack


716


is connected to a proximal side of the timing belt


732


, see connection point


752


, whereas the right rack


730


is connected to the other, or distal, side of the timing belt


732


, see connection point


754


. As a result, when the timing belt


732


is advanced in the direction of arrow


756


(clockwise), the left rack


716


and the right rack


730


are moved away from each other to thereby disengage from a plate


10


that is located between the left wheels


712


-


1


and the rights wheels


712


-


2


.




In contrast, when the timing belt is driven by the motor


738


to move in the direction of arrow


758


(counterclockwise), the right rack


716


and the left rack


730


are moved toward each other to thereby bring the wheels


712


-


1


,


712


-


2


into engagement with the plate


10


on the conveyer


710


. This results in the plate


10


being centered on the conveyor


410


and brought into angular alignment.




While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.



Claims
  • 1. A registration system for center registration of a printing plate being transferred via a substrate transfer system to an exposure machine, the registering system comprising:a set of moveable left engaging members comprising left wheels for moving to engage a left side of the printing plate; a set of moveable right engaging members comprising right wheels for moving to engage a right side of the printing plate; a moveable left rack for supporting the set of left engaging members; a moveable right rack for supporting the set of right engaging members; one or more rails for supporting and allowing movement of the left and right racks towards and away from one another, said rails supporting the left and right racks in parallel with one another and said rails longitudinally extending in parallel to a direction of travel of the printing plate being transferred; and a rack drive motor for simultaneously moving the left and right racks towards one another along the one or more rails, causing one of the sets of left and right engaging members to engage and center the printing plate along the substrate transfer system.
  • 2. The registration system as claimed in claim 1, wherein the exposure machine is an imaging engine.
  • 3. The registration system as claimed in claim 1, wherein the left and right engaging members move in a direction that is perpendicular to the direction of travel of the printing plate being transferred.
US Referenced Citations (8)
Number Name Date Kind
2528106 Albrecht Oct 1950 A
3897053 Guy Jul 1975 A
4311304 Hamada et al. Jan 1982 A
4506879 Goodwin et al. Mar 1985 A
4657239 Ikesue Apr 1987 A
5098081 DeFigueiredo Mar 1992 A
6209866 Hosking et al. Apr 2001 B1
20020140802 Yamada Oct 2002 A1
Foreign Referenced Citations (1)
Number Date Country
1306331 May 2003 EP