SYSTEM AND METHOD FOR SLIP SHEET EVACUATION

Abstract

A system and method for slip sheet disposal from a plate imaging device or printing device comprises a slip sheet dispensing means configured for dispensing the slip sheets from the plate imaging device and an air release module configured to apply air flow between the slip sheets and the slip sheet sliding tray during the slip sheets dispensing from the plate imaging device or printing device.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

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.

FIELD OF THE INVENTION

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.

BACKGROUND OF THE INVENTION

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 FIG. 1 that shows a side view of a system for disposing of slip sheets in a CTP imaging device according to the prior art in which slip sheet 14 is brought into disposal system 10. Slip sheet 14 is clamped using a slip sheet clamp 11 to a roller 12. Roller 12 radial movement evacuates slip sheet 14 outside system 10 towards direction 15.

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.

SUMMARY OF THE INVENTION

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

• • comprising: dispensing a slip sheet from a plate stack;
  • sliding the slip sheet over the tray; and
  • outputting air flow between the slip sheet and the tray.

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.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 is schematic illustration of a slip sheet disposal system according to the prior art;

FIG. 2 is a is a schematic illustration of a CTP imaging device that comprises the system according to some embodiments of the present invention;

FIG. 3 is schematic illustration of a slip sheet disposal system equipped with air jets according to some embodiments of the present invention;

FIG. 4 is schematic illustration of a slip sheet disposal system equipped with an evacuation path exhibiting air flow opening according to some embodiments of the present invention; and

FIG. 5 is a high level flow chart showing a method according to some embodiments of the present invention.

The drawings together with the description make apparent to those skilled in the art how the invention may be embodied in practice.

DETAILED DESCRIPTION OF THE INVENTION

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.

FIG. 2 shows a schematic view of a CTP imaging device 20 configured with an automatic plate loader in accordance with embodiments of the present invention. Plate stack 21 is shown inside CTP imaging device 20. Each plate in plate stack 21 comprises a metal based plate separated by slip sheet 14 (not shown). Slip sheet 14 is separated from the plate before imaging. Separated slip sheet 14 is removed from imaging device 20 by a slip sheet disposal system (not shown) with air release means (not shown). The disposal system is integrated inside imaging device 20.

FIG. 3 shows a schematic side view of a slip sheet disposal system 30 according to some embodiments of the invention. Sheet disposal system 30 comprises a slip sheet clamp 11 operatively associated with a plate stack (not shown), a roller 12, on which slip sheet clamp 11 is abutted, and a sliding slip sheet tray 13 located in proximity to roller 12 such that slip sheet 14 may be easily transferred from roller 12 to sliding slip sheet tray 13. Slip sheet disposal system 30 further comprises an air release module that may comprise a compression module 33 coupled to a conduit 31 located and arranged to output an air flow between sliding slip sheet tray 13 and slip sheet 14.

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.

FIG. 4 shows a schematic top view of the slip sheet disposal system according to some embodiments of the invention. Sheet disposal system 30 comprises slip sheet dispenser 11, roller 12 and slip sheet sliding tray 13 as detailed above. Slip sheet sliding tray 13 comprises a plurality of opening 40 located throughout its surface. Air compression module (not shown) is arranged to output air flow through plurality of openings 40 wile roller 12 slides slip sheet 14 over slip sheet sliding tray 13. The air flow from openings 40 flow in a perpendicular direction to the direction of sliding of slip sheet 14. This arrangement maximizes that impact of the air flow in separating slip sheet 14 from slip sheet sliding tray 13.

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.

FIG. 5 shows a high level flow chart showing the steps in a method of facilitation the sliding of a slip sheet from a plate stack over a tray within an imaging device, according to some embodiments of the present invention. The method comprising: dispensing a slip sheet from a plate stack 51; sliding the slip sheet over the tray 52; and outputting air flow between the slip sheet and the tray 53.

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.

Parts List

• 10—slip sheet disposal system—prior art
• 11—slip sheet clamp
• 12—roller
• 13—sliding slip sheet tray
• 14—slip sheet
• 15—slip sheet movement direction
• 20—CTP imaging device configured with an automatic plate loader
• 21—Plate stack
• 30—slip sheet disposal system with air jet
• 31—conduit
• 32—air between slip sheet and slip sheet tray
• 33—air compression module
• 35—air cushion
• 40—air flow openings

Claims

1. 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 clamp and a roller arranged in cooperation to pull a slip sheet from the plate stack and slide it on top of a slip sheet sliding tray;

an air release module operatively associated with the slip sheet sliding tray, wherein a slip sheet dispensing means is arranged to dispense the slip sheet from the plate stack 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.

2. (canceled)

3. The system according to claim 1, wherein the air release module comprises an air compression module coupled to an air dispensing means.

4. The system according to claim 3, wherein the air compression module is internal.

5. The system according to claim 3, wherein the air compression module is external.

6. The system according to claim 3, wherein the air dispensing means is a conduit located and shaped such that air flow is outputted as an air jet in the direction of the sliding of the slip sheet.

7. The system according to claim 6, wherein the air dispersion means further comprises an air nozzle.

8. The system according to claim 6, wherein the conduit end as narrower than the conduit.

9. The system according to claim 8, wherein the conduit end exhibits an aperture of an ellipsoidal shape.

10. The system according to claim 3, wherein the air dispersion means comprises a plurality of openings located on the top surface of the slip sheet sliding tray and wherein the air compression module is arranged to output an air flow through the plurality of openings.

11. The system according to claim 1, wherein the top surface of the slip sheet sliding tray is a straight surface.

12. The system according to claim 1, wherein the top surface of the slip sheet sliding tray is a curved surface.

13. The system according to claim 1 wherein the top surface of the slip sheet sliding tray is a combination of a straight and a curved surface.

14. The system according to claim 1, wherein the system is incorporated within an imaging device.

15. The systems according to claim 1, wherein the system is incorporated within a computer-to-plate imaging device.

16. A method of facilitation sliding of a slip sheet from a plate stack over a tray within an imaging device, the method comprising:

dispensing a slip sheet from a plate stack;

sliding the slip sheet over the tray; and

outputting air flow between the slip sheet and the tray.

17. (canceled)

18. The method of claim 16, wherein outputting of air flow between the slip sheet and the tray is in the direction parallel to the sliding direction of the slip sheet.

19. The method of claim 16, wherein outputting of air flow between the slip sheet and the tray is in the direction perpendicular to the sliding direction of the slip sheet.