Patent Application
20100032884
The present invention relates to a plate imaging devices, and more particularly, to systems configured to properly evacuate separated slip sheets from plate imaging devices.
Prior to setting forth the background of the invention in detail, it may be helpful to set forth definitions of certain terms that will be used hereinafter.
The term “Computer to plate” (hereinafter: CTP) as used herein in this application, relates to an imaging technology used in modern printing processes. In this technology, an image created in a Desktop Publishing application is output directly to a printing plate. CTP as used hereinafter relates also to the imaging device carrying the process of outputting the computer-stored image on the printing plates.
The term “Printing Plates” (sometimes referred to as “plate” or “plates”) as used herein in this application, relates to the flexible aluminum or plastic precursor printing plate elements that are imaged and developed to form lithographic printing plates that are then used in off-set printing technology. Traditional printing plates have a brushed or roughened texture and are covered with a photosensitive emulsion. A photographic negative of the desired image is placed in contact with the emulsion and the plate is exposed to light. After development, the emulsion shows a reverse of the negative image, which is thus a duplicate of the original (positive) image. The image on the plate emulsion can also be created through direct laser imaging in a CTP imaging device. Printing plates are typically stacked in a cassette, on a pallet or similar container which houses the plates and facilitates their protection, transportation, and handling, before loading them into a dedicated tray within a CTP imaging device.
The term “Slip Sheet” (hereinafter: “slip sheet”) as used herein in this application, relates to interleaves, usually in the form of paper sheets that are packed between the printing plates and are used to separate the plates. Slip sheets are also known in the industry as: “separation papers”, “slip sheets”, “slip papers”, or “leaf sheets”.
Every CTP imaging device usually comprises trays for accommodating the printing plates exhibiting specific dimensions. Trays can usually be arranged to contain plates of various sizes, but all plates in the same tray are of one size. The plates may be manually removed from the cassette, pallet or a shipping container and then inserted into the trays for use by the CTP imaging device.
After the plates are loaded into a CTP imaging device tray and prior to the plate loading, the slip sheet is removed from the loaded plate. According to the traditional art, the slip sheet is removed from the CTP device using a slip sheet disposal system. Such a traditional system is illustrated in
Due to the currently available structure, slip sheet 14 may be charged with static electricity, accumulated during plate packaging or plate shipment. In this case slip sheet 14 may be undesirably attached to the sliding tray 13 thus blocking the evacuation path of imminent slip sheets.
Therefore, there is a recognized need for a slip sheet disposal system equipped with means to avoid accumulated static electricity.
According to one aspect of the present invention, there is provided a system for facilitating slip sheets disposal using air flow, the system being operatively associated with a plate stack comprising plates separated by slip sheets, the system comprising: a slip sheet dispensing means; a slip sheet sliding tray operatively associated with the a slip sheet dispensing means; an air release module operatively associated with the slip sheet sliding tray, wherein the slip sheet dispensing means is arranged to dispense a slip sheet from the plate track and slide it on top of the slip sheet sliding tray; and wherein the air release module is arranged to output air flow between the top of the slip sheet sliding tray and the slip sheet thus facilitating the sliding of the slip sheet over the slip sheet sliding tray.
This invention also provides a method of facilitation sliding of a slip sheet from a plate stack over a tray within an imaging device, the method
These and other objects, features, and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.
The subject matter regarded as the invention will become more clearly understood in light of the ensuing description of embodiments herein, given by way of example and for purposes of illustrative discussion of the present invention only, with reference to the accompanying drawings (Figures, or simply “FIG.”), wherein:
The drawings together with the description make apparent to those skilled in the art how the invention may be embodied in practice.
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. However, it will be understood by those skilled in the art that the teachings of the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the teachings of the present disclosure.
The present invention describes a slip sheet removal system integrated in a CTP imaging device. The invention enables smooth slip sheets removal from the imaging device, avoiding jams in the slip sheet removal path, typically created due to accumulated static electricity and to friction between slip sheet and slide element.
In operation, roller 12, by rotating on the plate stack 21, lifts the top slip sheet 14 off the plate stack 21 and forces it in between clamp 11 and roller 12. Roller 12 continues to rotate causing the transfer of slip sheet 14 to the top side of sliding slip sheet tray 13. Then, air compression module 33 is arranged to output an air flow 32 via conduit 31 to the space defined by the top surface of sliding slip sheet tray 13 and slip sheet 14. Air flow 32 electrically insulates slip sheet 14 from sliding slip sheet tray 13 thus preventing any static electricity based or friction based attachment of slip sheet 14 to sliding slip sheet tray 13 which may result in slip sheet jamming.
According to some embodiments of the invention. Air flow 32 is applied in synchronization with the removal of slip sheet 14 by roller 12. Specifically, the synchronized action of rolling roller 12 and air compression module 33 is arranged to create an air cushion 35 between slip sheet 14 and sliding slip sheet tray 13. As explained above air cushion 35 prevents any contact between slip sheet 14 and sliding slip sheet tray 13 throughout the removal process of slip sheet 14. Thus, air cushion 35 enables smooth removal of slip sheet 14 from imaging device 20.
According to some embodiments of the invention, the air compression module may be internal and contained within the imaging device or alternatively, the compressed air may be supplied from an external source.
According to some embodiments of the invention, conduit 31 is located and shaped such that air flow is outputted as an air jet in the direction of the sliding of the slip sheet.
According to some embodiments of the invention, the air dispersion means further comprises an air nozzle so that the air flow may be optimally shaped to facilitate the separation of slip sheet 14 from slip sheet sliding tray 13.
According to some embodiments of the invention, the air dispersion means further comprises another conduit which is narrower than the first conduit. This enables further control over the flow of the air and may be arranged to output a high speed flow capable of easy separation of slip sheet 14 and slip sheet sliding tray 13.
According to some embodiments of the invention, the narrower conduit as explained above exhibits an aperture of an ellipsoidal shape.
According to some embodiments of the invention top surface of the slip sheet sliding tray may be a straight surface, a curved surface or any combination thereof.
Advantageously, the aforementioned slip sheet disposal system is incorporated within an imaging device and preferably, a CTP imaging device. However, it is understood that the disclosed system may be easily fitted into other devices requiring the quick and easy disposal of slip sheets from a stack of elements that are separated by slip sheets.
According to some embodiments of the invention, sliding the slip sheet over the tray and outputting air flow between the slip sheet and the tray occur in synchronization as so to optimize the impact of the air flow on facilitation of the separation of slip sheet 14 from slip sheet sliding tray 13.
According to some embodiments of the invention, outputting of air flow between the slip sheet and the tray may be in the direction parallel to the sliding direction thus applying thrust on slip sheet 14 in the advancement direction of the sliding.
According to some embodiments of the invention, outputting of air flow between the slip sheet and the tray may be in the direction perpendicular to the sliding direction of the slip sheet. This will maximize the impact of the air flow in separating slip sheet 14 from slip sheet sliding tray 13.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention.
While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention. Accordingly, the scope of the invention should not be limited by what has thus far been described, but by the appended claims and their legal equivalents.
Reference is made to commonly-assigned co-pending U.S. patent application Ser. No. 12/045,061, filed Mar. 10, 2008, entitled: “Plate Pallet Stock Detection”, by Korolik et al., the disclosure of which is incorporated herein by reference in its entirety.
