1. Field of the Invention
The present invention relates generally to systems and methods for utilizing a cassette cart and tray used in connection with, for example, Computer-to-Plate (CTP) imaging systems.
2. Background Description
Automating the printing process in Computer-to-Plate (CTP) imaging systems involves the alternating process of extracting plate sheet material, and then interleaf sheet material, from a material stack. Images are exposed on the plate sheet material, and the interleaf sheet material is used to protect the imaging surface of plate sheets from each other.
Interleaf sheets, though varying from manufacturer to manufacturer in material characteristics such as smoothness, porosity, and color, are generally paper-like with a thickness of about 0.003 inches. Plate sheet material typically varies in thickness from 0.005 inches to 0.014 inches.
Extracting the plate sheets and interleaf sheets manually is labor intensive, but normally does not present other issues or challenges. Plate sheets and/or interleaf sheets may be automatically removed by using, for example, a “pick and drag approach” that generally includes precise plate lifting at a controlled rate and height, air blowing to create an air cushion between the bottom of the plate and top of the slipsheet, static brushes, and air ionization to help neutralize static. All these events can vary in time and intensity depending on the plate dimensions (length, width, and thickness) and/or the height needed to lift and clear the inherent cassette containment wall depth.
Plate sheet cassettes typically hold approximately 60 plates and slipsheets. If a plate is 0.012 inches thick and a slipsheet is 0.003 inches thick, this amounts to a relatively shallow depth to overcome when picking up plates and slipsheets that are located toward the bottom of the cassette. However, even within this relatively shallow range of depth, the events can be numerous and complex, as described above. I have determined that the “pick and drag approach,” for example, becomes even more challenging and less reliable when plate sheets and interleaf sheets are extracted from a deeper (higher capacity) cassette. I have determined, therefore, that a system such as a cassette cart and tray that holds plate sheets that can, for example, keep plate sheets at a constant height as they are removed from the tray would facilitate removing plate sheets and interleaf sheets from a cassette.
Embodiments of the present invention relate generally to Computer-to-Plate (CTP) imaging systems and, more particularly, to systems and methods for enabling the top of the plate/interleaf stack height to remain relatively close to the opening of the cassette tray to maintain or substantially maintain the same pick-up mechanism lift height.
One or more embodiments of the present invention allow the top of the plate sheet/interleaf sheet stack height to remain relatively close to the opening of the cassette to minimize and maintain the same or substantially the same pick-up mechanism lift height. An entire stack of imaging plates and alternating interleaf sheets are thus raised as they are removed from the top of the cassette, to keep the top imaging plate within the stack at a same or substantially same position as imaging plates are removed from the stack. Embodiments of the present invention thus advantageously simplify removing a plate sheet from a cassette, since successively removed imaging plates will be at a same or substantially same height, and will thus not have to be lifted increasing amounts to clear cassette walls.
One or more embodiments of the present invention also advantageously maintain the ability of the image cassette cart to be separable from the lift mechanism and imaging system, while retaining its light tight feature. Additional features include provision for allowing for varying size plates/slipsheets, detection of a presence quantity of imaging plates, and adjustment capabilities.
In one embodiment of the invention, an apparatus includes a mobile cart assembly, and a cassette tray adapted for use with the mobile cart assembly. The cassette tray includes a plurality of sides, with each side having a through slot, and a bottom surface that has a first plurality of slots sized to receive a respective plurality of plate stops capable of maneuvering within the plurality of slots, and a second plurality of slots sized to respectively receive a plurality of lift arms.
In addition, the cassette has a platform that has a same plurality of sides as the cassette tray, and a same first plurality of slots as the bottom surface that are aligned with the first plurality of slots of the bottom surface. The platform is positioned within the cassette tray to contact the plurality of lift arms. A plurality of guide blocks, extending outwardly from each of the plurality of sides of the platform, sized to fit in the through slots, facilitate movement of the platform within the cassette tray.
The apparatus can also have a first door that contacts at least two of the plurality of sides, and covers at least a portion of the platform. The first door can slide in a first direction and a second direction with respect to the cart assembly to respectively expose and cover at least a portion of the platform.
The apparatus can have a second door that contacts at least one of the plurality of sides, and covers at least a portion of the platform. The second door can rotate about an axis in a first direction and a second direction to respectively expose and cover at least a portion of the platform.
The cassette tray can have a plurality of rails that contact a first side of the platform to facilitate insertion and removal of the cassette tray into and out of the cart assembly. The cassette tray can also have a plurality of detents that contact the first side of the platform. The plurality of detents can be used to facilitate positioning of the cassette cart with respect to an imaging system.
The cassette tray can also have a plurality of support bars that contact a first side of the platform. At least one of the plurality of guide blocks can be coupled to each of the plurality of support bars. In addition, a plurality of support bars can contact a first side of the platform. Each of the plurality of support bars can have at least one guide block. In addition, a first side of the platform can have coupled or affixed thereto a plurality of support covers respectively positioned to contact the plurality of lift arms.
A method in accordance with an embodiment of the present invention includes providing a cassette tray, adapted for use with the mobile cart assembly, that has a plurality of sides with through slots, and a bottom surface that has a first plurality of slots sized to receive a respective plurality of plate stops capable of maneuvering within the plurality of slots, and a second plurality of slots sized to respectively receive a plurality of lift arms.
A platform is provided that has a same plurality of sides as the cassette tray, and a same first plurality of slots as the bottom surface that are aligned with the first plurality of slots of the bottom surface. The platform is positioned within the cassette tray to contact the plurality of lift arms.
A plurality of guide blocks, extending outwardly from each of the plurality of sides of the platform, are provided that are sized to fit in the through slots, to facilitate movement of the platform within the cassette.
The Detailed Description including the description of preferred structures as embodying features of embodiments of the invention will be best understood when read in reference to the accompanying figures wherein:
Lift mechanism arms are used to raise and lower platform 520 within cassette 300 as described, for example, in connection with
In particular, shim 420d is positioned between side 410a and L-shaped transverse member 418. The thickness of shim 420d can be varied to raise or lower imaging cassette cart 200. Multiple shims (not shown) of a same or varying thickness may also be used to achieve desired height of imaging cassette cart 200. Of course, shims do not need to be utilized if imaging cassette cart 200 is at a desired height without them. Securing bracket 422d can be used to secure shim 420d in place. Securing brackets 422a-c and shims 420a-c can be respectively configured in a same or similar manner as shim 420d to achieve a desired height of imaging cassette cart 200.
On platform 520, guide blocks 502a-d are located, for example, at or near the center of each side of platform 520. Guide blocks 502a-d can respectively slide inside through slots 704a, 704b shown in
Supports 508a-d can provide contact areas for lift mechanism arms (one lift arm mechanism for each of supports 508a-d) to raise and lower platform 520. Supports 508a-d can also serve to distribute the plate sheet 106 load.
Platform 520 may also have a hole 510 that may be used to detect whether a plate sheet 106 is on the top of the stack, an interleaf sheet is on the top of the stack, or that nothing is on platform 520. For example, a standard reflective-type sensor can be placed on apparatus 104. The sensor can be positioned to detect or “read” light reflected from a plate sheet 106 or interleaf sheet. If a plate sheet 106 is on the top of the stack, a first signal will be reflected back to the sensor. If an interleaf sheet is on the top of the stack, a second type of signal will be reflected back to the sensor. If neither a plate sheet 106 nor an interleaf sheet is on platform 520, hole 510 will be exposed, thereby providing a third signal to the sensor, indicating that nothing is on platform 520.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. While the foregoing invention has been described in detail by way of illustration and example of preferred embodiments, numerous modifications, substitutions, and alterations are possible without departing from the scope of the invention defined in the following claims.