Information
-
Patent Grant
-
6801302
-
Patent Number
6,801,302
-
Date Filed
Monday, January 6, 200322 years ago
-
Date Issued
Tuesday, October 5, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Sabourin; Robert A.
- Houston; J. Grant
-
CPC
-
US Classifications
Field of Search
US
- 271 13
- 271 228
- 271 255
-
International Classifications
-
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)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1306331 |
May 2003 |
EP |