WO2008088818A1

WO2008088818A1 - High speed plate pick up device

Info

Publication number: WO2008088818A1
Application number: PCT/US2008/000551
Authority: WO
Inventors: Todd Kepple; James A. Dougherty
Original assignee: Ecrm, Inc.
Priority date: 2007-01-17
Filing date: 2008-01-16
Publication date: 2008-07-24

Abstract

A system for removing an interleaf sheet contacting a plate sheet used in an imaging system, comprised of a substantially horizontal member; an assembly comprising at least two elements configured to directly contact and pick up the interleaf sheet, a portion of said assembly connected to said member; a motor configured to move said member in a direction substantially perpendicular to a surface of the interleaf sheet as positioned prior to contact; and a first sensor system that generates a signal indicating when said member is a first predetermined distance from the interleaf sheet; and a second sensor system comprised of a second sensor that generates a signal indicating that the sheet beneath the second sensor is an interleaf sheet; said motor utilizing the first predetermined distance to move said member a second predetermined distance from the interleaf sheet, the at least two elements not contacting each other at the second predetermined distance, said motor moving said member in a direction toward the first predetermined distance to a position where at least a portion of the interleaf sheet is interposed between the at least two elements.

Description

HIGH SPEED PLATE PICK UP DEVICE

Cross-Reference to Related Patent Applications

This patent application claims priority based upon patent application 60/880,893, the entire disclosure of which is hereby incorporated by reference into this specification. This application also is a continuation-in-part of applicants' copending patent application U.S.S.N. 11/296,527, filed on December 8, 2005, which was published as (U.S. 2006/0117975) on June 8, 2006. The entire disclosure of such patent application is hereby incorporated by reference into this specification. Technical Field

A system for removing and/or separating an interleaf sheet from a plate sheet and/or transporting a plate sheet that is used in conjunction with, e.g., a Computer-to-Plate imaging system. Background Art

Published United States patent application US 2006/0117975 relates generally to a system and method for removing and/or separating an interleaf sheet from a plate sheet and/or transporting a plate sheet, used in connection with, for example, Computer-to-Plate (CTP) imaging systems. As is described in paragraph 0005 of such published patent application, "Automating the printing process in 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."

In paragraph 0007 of such patent application, it is disclosed that "Extracting the interleaf sheets manually is labor intensive, but normally does not present other issues or challenges. However, automating the process for extracting interleaf sheets can be challenging. For example, interleaf sheets can adhere onto the imaging surface of the plate sheet because of, for example, friction and/or static. Known CTP systems that automate the removal of interleaf sheets, such as disclosed in U.S. Pat. No. 5,655,452, which is in incorporated herein by reference, use at least a combination of a suction cup and air blast. However, due to the porous nature of the interleaf sheet, reliability issues are generally present when suction cups are used to remove interleaf sheets." Claim 1 of published patent application US 2006/0117975 discusses a system for removing an interleaf sheet, describing: "1. A system for removing an interleaf sheet contacting a plate sheet used in an imaging system, comprising: a substantially horizontal member; an assembly comprising at least two elements configured to directly contact and pick up the interleaf sheet, a portion of said assembly connected to said member; a motor configured to move said member in a direction substantially perpendicular to a surface of the interleaf sheet as positioned prior to contact; and a sensor system that generates a signal indicating when said member is a first predetermined distance from the interleaf sheet; said motor utilizing the first predetermined distance to move said member a second predetermined distance from the interleaf sheet, the at least two elements not contacting each other at the second predetermined distance, said motor moving said member in a direction toward the first predetermined distance to a position where at least a portion of the interleaf sheet is interposed between the at least two elements."

Claim 36 of published patent application US 2006/0117975 discusses a system for picking up plate, describing: "36. A system for raising a plate sheet for use in. an imaging system comprising an imager, comprising: a substantially horizontal member; at least one element configured to directly contact and vertically raise the plate sheet, a portion of said at least one element connected to said member; a motor configured to raise said member in a direction substantially perpendicular to a surface of the plate sheet as positioned prior to contact; and a sensor system that generates a signal indicating when said member is a first predetermined distance from the plate sheet; said motor utilizing the first predetermined distance to move said member a second predetermined distance, thereby raising the plate sheet."

Claim 41 of published patent application US 2006/0117975 depends upon such claim 36 and further describes a rail system for moving the plate sheet as follows: "41. The system according to claim 36, further comprising a rail system for moving the plate sheet in a direction away from the imager, to thereby substantially align a trailing edge of the plate sheet with a trailing edge of a second plate sheet positioned beneath said plate sheet."

The devices utilized in the prior art (such as, e.g., the devices described by such claims 1, 36, and 41) utilize a one-arm assembly to pick up plates out of a cassette and transfer them into an imaging system; that same arm assembly is also used to pick up interleaf sheets and dispose the interleaf sheets into a chute. As described hereinabove, and with reference to such published patent application, claim 1 describes the system for removing the interleaf sheets, claim 36 describes the system for picking up plates, and claim 41 describes the rail system that the arras travels on. The published patent application patent shows both the interleaf removal mechanism and the plate pick mechanism on the same arm assembly.

It is an object of this invention to provide a device with a substantially greater speed of operation than the prior art devices and, in particular, than the device disclosed in published United States patent application 2006/0117975. Disclosure of the Invention

In accordance with this invention, there is provided a system for removing an interleaf sheet contacting a plate sheet used in an imaging system, comprised of a substantially horizontal member; an assembly comprising at least two elements configured to directly contact and pick up the interleaf sheet, a portion of said assembly connected to said member; a motor configured to move said member in a direction substantially perpendicular to a surface of the interleaf sheet as positioned prior to contact; and a first sensor system that generates a signal indicating when said member is a first predetermined distance from the interleaf sheet; and a second sensor system comprised of a second sensor that generates a signal indicating that the sheet beneath the second sensor is an interleaf sheet; said motor utilizing the first predetermined distance to move said member a second predetermined distance from the interleaf sheet, the at least two elements not contacting each other at the second predetermined distance, said motor moving said member in a direction toward the first predetermined distance to a position where at least a portion of the interleaf sheet is interposed between the at least two elements. Brief Description of the Drawings

The invention will be described by reference to specification and the accompanying Figures, in which like numerals refer to like elements, and wherein:

Figure 1 is a perspective view of a Computer-to-Plate (CTP) imaging system;

Figure 2 is a perspective view of an exemplary interleaf sheet removal and plate sheet transport apparatus;

Figure 3 is a second perspective view of the exemplary interleaf sheet removal and plate sheet transport apparatus, and disposal rollers;

Figure 4 is a perspective view of an exemplary embodiment of an interleaf sheet removal roller apparatus;

Figures 5A-5D is a sequence of operations showing how the interleaf sheet removal roller apparatus can be used to pick up an interleaf sheet;

Figure 6A is a front view of a second embodiment of an interleaf sheet removal roller apparatus;

Figure 6B is a perspective view of a second embodiment of an interleaf sheet removal roller apparatus;

Figure 7A is a front view of a third embodiment of an interleaf sheet removal roller apparatus;

Figure 7B is a perspective view of a third embodiment of an interleaf sheet removal roller apparatus;

Figures 8A-8D is a sequence of operations showing how a fourth embodiment of an interleaf sheet removal roller apparatus can be used to pick up an interleaf sheet;

Figure 9 is a perspective view of a second embodiment of an exemplary interleaf sheet removal apparatus;

Figure 10 is a second perspective view of a second embodiment of an exemplary interleaf sheet removal apparatus;

Figures 1 IA-I ID is a sequence of operations showing how a second embodiment of the interleaf sheet removal apparatus can be used to pick up an interleaf sheet;

Figure 12 is a perspective view of a preferred Computer-to-Plate (CTP) imaging system;

Figure 13 is a perspective view of a high speed dual pick-up arm apparatus that preferably comprises the system of Figure 12;

Figure 14 is an enlarged perspective view of the pick-up arm apparatus of Figure 13;

Figure 15 is a perspective view of a plate pick-up apparatus that preferably comprises the system of Figure 12;

Figure 16 is a perspective view of an interleaf removal apparatus that preferably comprises the system of Figure 12; and

Figure 17 is a schematic of an interleaf disposal and scissor release system that preferably comprises the system of Figure 12.

Best Mode for Carrying Out the Invention

The present invention relates generally to a system and method for removing and/or separating an interleaf sheet from a plate sheet and/or transporting a plate sheet, used in connection with, for example, Computer-to-Plate (CTP) imaging systems.

Figure 1 is a perspective view of a Computer-to-Plate (CTP) imaging system 100 that can be used in connection with the interleaf sheet removal and plate sheet transport apparatus 114 (apparatus 114) and/or portions thereof in accordance with certain embodiments of the present invention. The system 100 includes a cassette assembly 102 that can hold plate sheets (not shown) and associated interleaf sheets (not shown). Cassette interface 104 can be used to load the cassette assembly 102 with alternating plate sheets and interleaf sheets in a conventional manner. Apparatus 114 can be used to remove interleaf sheets from plate sheets, remove plate sheets from interleaf sheets, dispose the interleaf sheets in funnel assembly 106, and/or transport plate sheets to input shelf 108. Vacuum pump 118 is used to generate a suction so that suction cups can hold and transport a plate sheet. When the plate sheets are received at input shelf 108, imaging apparatus 110 generally utilizes one or more lasers to perform plate sheet imaging in a conventional manner. Output platform 112 receives imaged plate sheets.

Figures 2 and 3 show perspective views of apparatus 114. Apparatus 114 includes member 202, which can be used to receive a portion of roller assemblies 200a, 200b. Roller assemblies 200a, 200b can be used to pick up and remove interleaf sheets, as will be described below. Member 202 can also be used to receive a portion of suction cups 206a, 206b. Suction cups 206a, 206b can be used to pick up and remove plate sheets 335, and feed (transport) them to input shelf 108 and imaging apparatus 110. Prior to roller assemblies 200a, 200b picking up an interleaf sheet, an interleaf sheet will be substantially horizontal, as plate sheet 335 is shown in Figure 3.

Rail apparatus 116 can be used to move apparatus 114 in the direction of arrows 226, 228. Optical sensor 244, which can be mounted in a fixed position, and having teeth 244a, 244b, can be used to control movement of apparatus 114. Flag 248 can be received between teeth 244a, 244b to block an optical signal between the teeth. When the optical circuit is completed between teeth 244a, 244b, movement in direction 226, 228 can be stopped. Optical sensors 238, 240, and 242 can be configured the same as or similarly to sensor 244 to control movement and/or position, as will be described herein.

Rail apparatus 116 can include a mounting plate 222 which, in turn, is secured to member 250. Motor 208 is used to drive shaft 216 which, in turn, moves apparatus 114 in the direction of arrows 230, 232. Shaft 216 can be, for example, a conventional screw shaft. Member 250 can be attached to or be an integral part of mounting plate 222. Horizontal slide rail 218 can be attached to or an integral part of member 250. Vertical plate 252 can have an attachment or integral part thereof that mates with and receives horizontal slide rail 218 to facilitate movement of apparatus 114 in the direction of arrows 230, 232. The length of shaft 216 and/or collar 256 contact with member 202 can be used to limit movement of apparatus 114 in the direction of arrow 230. Flag 254 and sensor 242 are used to limit movement of assembly in the direction of arrow 232.

Sensor 238 may used to indicate that member 212 is at or near a home position. Flag 266 is attached to or integral with, for example, a bottom surface of motor mount 270. When member 212, having sensor 240 attached thereto, moves in the direction of arrow 236, a home position can be determined when flag 266 cuts of the signal between the teeth of sensor 238. In FIG. 2, member 212 is shown in the home position.

Motor 210 is used to drive shaft 258 which, in turn, moves apparatus 114 in the direction of arrows 234, 236. Shaft 258 may be, for example, a conventional screw shaft. Vertical position member 212 can have an attachment or integral part thereof that mates with and receives vertical slide rail 262 to facilitate movement of apparatus 114 in the direction of arrows 234, 236. Flag 248 and sensor 240 are used to determine the distance of member 202 from an interleaf sheet or plate sheet 335. The length of shaft 258 and/or collar 260 contact a top surface of motor 210, and is used to limit movement of apparatus 114 in the direction of arrow 234.

Plate height sensor member 205 can be used to determine the distance of member 202 from an interleaf sheet or a plate sheet 335. When sensor member 205 contacts an interleaf sheet or plate sheet 335, member 202 continues to move in the direction of arrow 234, and shaft 264 will remain stationary relative to interleaf sheet or plate sheet 335. Flag 248 can be attached to or integral with a top portion of shaft 248, such that as member 202 continues to move in the direction of arrow 234, flag 248 will block the optical signal of sensor 240. The blocking of the optical signal can be associated with a distance of member 202 to an interleaf sheet or plate sheet 335.

In the case of an interleaf sheet, motor 210 continues to drive member 202 in the direction of arrow 234, and thereby activate roller assemblies 200a, 200b, as will be described herein. Movement of member 202 in the direction of arrow 234 is not normally limited by collar 224 contacting a bottom surface of member 202 and/or collar 260 contacting a top surface of motor 210. Movement of member 202 in the direction of arrow 234 is of a predetermined distance, starting from the time when member 205 makes contact with the interleaf sheet, to the time when flag 248 blocks the optical signal of sensor 240. This predetermined distance may be optimized to best secure the interleaf sheet between rollers 202a, 204a and 202b, 204b. After an interleaf sheet is received between rollers 202a, 204a and 202b, 204b, motor 210 is used to raise apparatus 114 in the direction of arrow 236.

When apparatus 114 removes an interleaf sheet, rail apparatus 116 can then be activated to move apparatus 114 in the direction of arrow 226, to position the interleaf sheet over disposal rollers 302a, 302b. Disposal rollers can be driven by at least one motor and belt assembly (not shown) to rotate rollers 302a, 302b respectively in the direction of arrows 304a, 304b. Motor 210 can be used to lower apparatus 114 in the direction of arrow 234 so that the interleaf sheet contacts the disposal rollers 302a, 302b and conveys the interleaf sheet to rollers 302a, 302b. Upon disposing of the interleaf sheet, motor 210 can be used to raise apparatus 114 in the direction of arrow 236. Rail apparatus 116 can be used to move apparatus 114 in the direction of arrow 228, so that suction cups 206a, 206b can pick up a plate sheet 335, and feed the plate sheet 335 to input shelf 108 for subsequent imaging. hi the case of a plate sheet 335, vacuum pump 118, operatively connected to suctions cup 206a, 206b by, for example, one or more hoses, is activated. The suctions cups 206a, 206b, by vacuum, hold the plate sheet 335 in contact with the vacuum cups 206a, 206b. Movement of member 202 in the direction of arrow 234 is again limited by a predetermined distance. After an interleaf sheet is received between rollers 202a, 204b and 202b, 204b, motor 210 can be used to raise apparatus 114 in the direction of arrow 236.

Once the suction cups 206a, 206b contact a plate sheet 335, in one embodiment of the invention, the following sequential, non-sequential or sequence independent operations may take place. Referring to Figure 1, assembly 114 is moved in proximity to an edge of the plate sheet 335. An edge of the plate sheet 335 is preferred because static forces and vacuum forces are generally weaker there. Vacuum pump 118 is activated to provide a vacuum to suction cups 206a, 206b. Apparatus then moves in the direction of arrow 236, thus lifting plate sheet 335. hi one embodiment, the plate sheet 335 can be lifted approximately 10 mm.

The plate sheet 335 is held in the raised (in the direction of arrow 236) position for approximately 3-5 seconds, thereby allowing an interleaf sheet that may be adhering to a bottom surface of the plate sheet 335, in the vast majority of cases, to separate and fall back in to place to the stack. The interleaf may not fall/separate from the bottom of the plate sheet 335 in all instances. To minimize any relative motion between the interleaf sheet and the plate sheet 335 under these circumstances, apparatus 114, holding plate sheet 335, moves further in the direction of arrow 236, and slightly in the direction of arrow 228 to minimize or eliminate any sliding of the plate sheet 335 relative to the interleaf sheet underneath the plate. Relative motion may be caused by sagging at the opposing end of the plate sheet 335 from which the suction cups 206a, 206b are holding the plate sheet 335. The sagging causes the opposing end of the plate sheet 335 to drop vertically. The opposing edge of the plate sheet 335, by virtue of dropping vertically, also moves slightly toward suction cups 206a, 206b (in the direction of arrow 226), which is compensated for by the apparatus 114 moving in the direction of arrow 228.

Whether or not the interleaf sheet has dropped back to the stack or adheres to the bottom of the plate sheet 335, ionizer 272 is activated, which creates an air cushion. A compressed air cylinder (not shown) may be used in conjunction with ionizer 272, which causes static charges to dissipate. Any interleaf sheet that may have been adhering to the bottom of the plate sheet 335 will now fall back to the stack. In either case, static charges will be dissipated. Ionizer 272 can be operated for approximately 5 seconds to dissipate any static charges. Rail 116 is then engaged to move apparatus 114 and the plate sheet 335 in the direction of arrow 226, thereby moving the plate sheet 335 along the air cushion, and on to the input shelf 108 where the plate sheet 335 is positioned and released for imaging.

Figure 4, generally at 202, is a perspective view of an exemplary embodiment of an interleaf sheet roller assembly. Rollers 402, 404 can be provided with roller clutch bearings. The surface of rollers 402, 404 is preferably made of a rubber or rubber-like material suitable for gripping interleaf sheets. Urethane or a urethane-like material can be used.

Axles, preferably made of metal (e.g., stainless steel), are respectively received in holes 410, 412 of members 406, 408. The axles are also similarly received in corresponding holes (not shown) of members 414, 416. Members 406, 408 and 414, 416 rotate about hinge pin 446. Members 406, 408 and 414, 416 are respectively arranged in a scissors-like configuration. A recess 442 can be provided on members 406, 416 to limit the movement of members 408, 414 as the bottom portion of members 406, 408, 414, 416 move in the direction of arrows 448. Screws 434, 444 can be provided on members 406, 408, 414, 416 to hold the axles in place so that they do not rotate relative to members 406, 408, 414, 416. In this manner, roller clutch bearings (not shown) can be used to prevent rotation of rollers 402, 404 when rollers 402, 404 move towards each other, in the direction of arrows 424.

Member 436 and hinge pin 446 form a single piece. Rod 418 is operably connected and/or in contact with a cutout surface 438 of member 436 and hinge pin 446 such that when rod 418 is pushed in the direction of arrow 234, member 436 and hinge pin 446 can distribute the force to members 406, 408, 414, 416, thereby causing members 406, 408, 414, 416 to move in the direction of arrows 448.

Members 406, 408 are respectively provided with holes 432, 450. Members 414, 416 are provided with similar holes (not shown). Member 406 and its respective hole 432, and member 416 having a respective hole (not shown), receive link 430. Similarly, member 408 and its respective hole 434, and member 414 having a respective hole (not shown) receive link 428. One or more retaining rings 440 can be used to secure links 428, 430 to respective members 408, 414 and 406, 416. Springs 420, 422 are secured to links 428, 430 to provide a force in the direction of arrows 424. The force increases as rollers 402, 404 move in the direction of arrows 448. At equilibrium, springs 420, 422 can provide a force in the direction of arrows 424 such that rollers 402, 404 contact each other with some amount of pinch force. Figures 5A-5D show a sequence of positions of assembly 200 with respect to interleaf sheet 502. Figure 5A shows rollers 402, 404 contacting each other with some amount of pinch force, and contacting interleaf sheet 502. In Figure 5B, a force is applied to rod 418 in the direction of arrow 234, causing rollers 402, 404 to press outward in the direction of arrows 448.

Rollers 402, 404 rotate freely with minimal bearing friction when moving in the direction of arrows 448. When moving in the direction of arrows 448, rollers 402, 404 contact interleaf sheet 502, and can produce a constant or variable contact force.

At a point where the outward spacing of the rollers is sufficient to grasp interleaf sheet 502 as shown in Figure 5C at 508, the forces on the rollers are changed such that rollers 402, 404 maintain a downward force on interleaf sheet 502, while causing rollers 402, 404 to move toward each other in the direction of arrows 424.

When rollers move in the direction of arrows 424, they are not free to roll on interleaf sheet 502. In an embodiment, standard clutch bearings (not shown) coupled to rollers 402, 404 in a conventional manner can be used to provide unidirectional rotation of the rollers 402, 404 respectively in the direction of arrows 504, 506, and prevent rollers 202, 204 from rotating when they move in the direction of arrows 424. Because rollers 402, 404 do not rotate when they move in the direction of arrows 424, interleaf sheet 502 "buckles up" into a small loop, as shown at 508 in FIG. 5C. The force of rollers 402, 404 against interleaf sheet 502, together with the friction force created by the surface of rollers 402, 404 with respect to interleaf sheet 502, overcome resisting forces between interleaf sheet 502 and the plate sheet below (not shown). Resisting forces may include, for example, the column strength of interleaf sheet 502, static, suction, and/or frictional forces between interleaf sheet 502 and the plate sheet below. As shown in Figure 5D, springs 420, 422 (spring 420 is not shown in Figure ) pull rollers 402, 404 in the direction of arrows 424 until the rollers 402, 404 provide a pinch force that holds interleaf sheet 502 therebetween.

Figures 6A and 6B, generally at 600, respectively show a front view and perspective view of another embodiment of the invention. In particular, Figures 6 A and 6B shows stationary foot (or thick block) 602, which can be used in lieu of roller 402 shown in Figure 4. The positions of stationary foot 602 and roller 404 can also be switched. With the embodiment of Figures 6 A and 6B, curvilinear motion of rod 418 in the x-y plane replaces the simple linear motion of rod 418 in the direction of arrows 234, 236 in the embodiments of Figures 4 and 5A- 5D.

Figures 7A and 7B, generally at 700, respectively show a front view and perspective view of another embodiment of the invention. In particular, Figures 7 A and 7B shows stationary foot (or thin block) 702, which is used in lieu of roller 402 shown in Figure 4. The positions of stationary foot 702 and roller 704 can also be switched. With the embodiment of Figures 7 A and 7B, curvilinear motion of rod 418 in the x-y plane replaces the simple linear motion of rod 418 in the direction of arrows 234, 236 in the embodiments of Figures 4 and 5A- 5D.

Figures 8A-8D, generally at 800, shows another embodiment of the invention, and a sequence of positions of assembly 800 with respect to interleaf sheet 502. Figures 8A-8D show a substantially rigid Y-shaped link 806, and non-circular rollers 802, 804 with one-way rolling respectively in the direction of arrows 504, 506 when a force is applied to rod 418 in the direction of arrow 234. The embodiment of Figure 8 can be used to create a cam-like pinch force with respect to interleaf sheet 502. Rollers 802, 804 can be weighted and/or rolled about an axis offset from the axis of the main curvature of the roller. Roller clutch bearings (not shown) can also optionally be used with rollers 802, 804 to prevent rollers 802, 804 from respectively rotating in a direction opposite arrows 504, 506.

Figure 9, generally at 900, is a perspective view of second embodiment of an exemplary interleaf sheet removal apparatus. Pick up roller carriage 901 can include axles 902a, 902b. Rollers 904a, 904b can be configured concentrically about axles 902a, 902b, and rotate therewith. Rollers 904a, 904b can be positioned at or near the center of plate sheets 335 and interleaf sheets, and contact each other to facilitate removal of plate sheets 335 and interleaf sheets. One or more motors (not shown) can be used to drive the axles 902a, 902b respectively in the direction of arrows 920, 922.

Transfer housing 906a and 906b can be connected to or integral with connection housing 908. An optionally tapered opening 914 can be provided at an end of transfer housing 906a to receive interleaf sheets from pick up roller carriage 901. ^"One or more driven rollers Ia- If can be mounted to or integral with a first side of transfer housing 906a, 906b. Rollers Ia-If can be driven by a motor and belt (not shown). One or more blocks 924 can be connected to or integral with the first side of tranfer housing 906a, 906b, and rollers Ia-If can be connected to or integral with the respective blocks.

One or more non-driven rollers 2a-2f can be mounted to or integral with a second side of transfer housing 906a, 906b. Rollers Ia-If can contact rollers 2a-2f so that rollers 2a-2f rotate with driven rollers Ia-If. A block 926 can be connected to or integral with the second side of tranfer housing 906a, 906b, and rollers 2a-2f can be connected to or integral with the respective blocks.

A suction cup apparatus, generally at 910, can optionally be provided and/or utilized in connection with interleaf sheet removal apparatus 900. Suction cups 912a, 912b can be used to pick up plate sheets 335. Egress chute 918 can have a first end that receives interleaf sheets from transfer housing 906b, and a second end that allows the interleaf sheets to exit.

Figure 10, generally at 900, is a second perspective view of the second embodiment of an interleaf sheet removal apparatus. Rail system 1006 can be used to move pick up roller carriage 901 in the direction of arrows 1002, 1004.

Figures 11 A— 1 ID is a sequence of operations showing how apparatus 900 can be used to pick up an interleaf sheet. Pick up roller carriage 901 is positioned near plate sheet and interleaf sheet stack 1102. Rollers 904a, 904b, resting on an interleaf sheet, respectively rotate in the direction of arrows 920, 922 to remove an interleaf sheet 1104 from stack 1102. A disposal bin 1110 can be provided to receive interleaf sheet 1104 as it exits egress chute 918.

As is shown in Figure 1 IB, interleaf sheet 1104 is lifted off the plate stack by rotating rollers 904a, 904b. Interleaf sheet 1104 can be folded, and pulled up between rollers 904a, 904b. Rollers 904a, 904b can be stopped when a predetermined length of interleaf sheet 1104 has been fed therethrough. A sensor (not shown) can be used to indicate the predetermined length. For example, an optical sensor can be mounted above rollers 904a, 904b such that when interleaf sheet 1104 is fed through rollers 904a, 904b, interleaf sheet 1104 will interrupt the optical circuit, thereby indicating the predetermined length.

Figure 11C shows that interleaf sheet 1104 is removed from stack 1102 as interleaf sheet removal apparatus 900 traverses rails 1108a, 1108b in the direction of arrow 1106. Rollers 904a, 904b feed the leading edge of interleaf sheet 1104 to opening 914.

Figure 1 ID shows interleaf sheet 1104 being driven by rollers Ia-If, in conjunction with rollers 2a-2f to convey interleaf sheet 1104 through transfer housing 906a, connection housing 908, and transfer housing 906b. Rollers Ia-If and 2a-2f can continue to rotate until a trailing edge of interleaf sheet 1104 has cleared rollers Ia, 2a. A sensor, such as an optical sensor, positioned at or near rollers Ia, 2a, can be used to indicate when the sheet has cleared. As the trailing edge of interleaf sheet 1104 exits rollers Ia, 2a, interleaf sheet 1104 can be placed into disposal bin 1110. Interleaf sheet removal apparatus 900 can then move in the direction of arrow 1112, to return to the position shown in Figure 1 IA, and receive another interleaf sheet 1104. High speed dual pick up arm apparatus

In Figures 12 to 17, a high-speed dual pick up apparatus is described. A perspective view of such apparatus 1500 is presented in Figure 12.

The device depicted in Figures 12 to 17 preferably separates the interleaf removal mechanism from the plate pick up mechanism by utilizing two separate arm assemblies. The interleaf removal mechanism is on one arm assembly, and the plate pick up mechanism is on another arm assembly. The arms function independently of each other, but they both travel on the same rail system, thereby eliminating the cost of a second rail assembly. The rail is extended to accommodate the additional arm.

Separating the functions onto two arm assemblies allows the machine to load plates much faster into the imager than prior art devices because the arm does not have to let one operation finish before it starts the next. The arms work simultaneously to limit the waiting period between operations. This greatly increases throughput of the machine. In one embodiment, the CTP machine with the new dual pick up arm system can output 120 or more plates per hour compared to prior art machines, which typically output 60 plates per hour.

The operation of the new design is as follows: The plate pick up arm picks up a plate in the cassette using the vacuum cups and then brings the plate to the input shelf to be registered on the pins. As soon as the plate is out of the cassette, the interleaf sheet removal arm moves to pick up the interleaf sheet in the cassette. While the pick up arm is registering the plate against the pins, the interleaf sheet arm is picking up the interleaf sheet and the moving it to the disposal rollers and the rollers dispose the sheet in a holding bin below. The pick up arm finishes registering the plate and then only has to pause momentarily to allow the interleaf arm to finish disposing the interleaf sheet. Then the pick up arm can pick up the next plate.

The following figures show many of the same elements that are described in Figures 1- 11, and like elements are described by like numerals. In the remainder of this specification, only those elements which are not present in the prior Figures are discussed.

Figure 12 is a perspective view of a Computer-to-Plate (CTP) imaging system 1500 that is similar to the system 100 depicted in Figure 1 but differs therefrom in that the interleaf removal apparatus 2000 and the plate pick up apparatus 2001 are used in place of the interleaf sheet removal and plate sheet transport apparatus.

Figure 13 is a perspective view of one embodiment of a high-speed dual pick-up arm apparatus in a Computer-to-Plate (CTP) imaging system. The interleaf removal apparatus 2000 and the plate pick up apparatus 2001 are used in place of the interleaf sheet removal and plate sheet transport apparatus 114.

Figure 14 is a perspective view of one preferred embodiment of a high-speed dual pickup arm apparatus. The rail apparatus 116b is similar to the rail apparatus 116 depicted in the prior Figures, except it is preferably longer to accommodate the two arm assemblies and has additional features to support the additional apparatus. Gearmotor 2002a moves the plate pickup apparatus 2001 in the 226 and 228 direction. Gearmotor 2002b moves the interleaf removal apparatus in the 226 and 228 direction. Optical sensor 244 and flag 2248 (similar to element 248) are used to control the movement and position of the plate pick-up apparatus 2001. Optical sensor 2244 (similar to element 244) and flag 2003 are used to control the movement and position of the interleaf removal apparatus 2000. Mounting plates 2222a and 2222b are similar to mounting plate 222.

Figure 15 is a perspective view of the plate pick-up apparatus 2001. The plate pick-up apparatus is similar to the plate pick up and interleaf removal apparatus 114 described in the prior Figures except it has no means to pick up an interleaf sheet. Motors 2210a and 2208 and are similar to elements 210 and 208 described in the prior Figures except the motors are optimized to be faster and to have increased life. Plate height sensor member 2205a and shaft 2264a are similar to elements 205 and 264 described in the prior Figures. In the embodiment depicted, a third vacuum cup 206c is utilized to assist in registering the plate. Member 2202a is similar to member 202 of the prior Figures except it only has features for the vacuum cups.

Figure 16 is a perspective view of the interleaf removal apparatus 2000. The interleaf removal apparatus uses the same scissor roller assemblies 200a and 200b described in the prior Figures to pick up the interleaf sheet as apparatus 114. Optical sensors 2006 are used to tell when there is an interleaf sheet being held in the roller assembly 200a and 200b. Optical sensors 2206 are used to tell that the sheet beneath the interleaf removal apparatus is indeed an interleaf sheet as opposed to a plate sheet or other unexpected sheet. The interleaf removal apparatus 2000 has no vacuum cups to pick up plates and it does not need to move in the 230 and 232 directions depicted in the published patent application. Member 2202b is similar to member 2202a and 202. Motor 2210b is the same type motor as 2210a and the method to raise and lower member 2202b in directions 234 and 235 is similar to the method to raise and lower members 2202a and 202 on apparatus 2001 and 114. Spring plungers 1208 and 2005 assist in inserting interleaf sheets between the disposal rollers 302a and 302b (see Figure 17).

Figure 17 is a side view of a portion of Figure 13, showing interleaf sheet 502 being released and disposed; this interleaf scissor mechanism is similar to the mechanism shown in Figures 13-16 of published United States patent application 2006/0174790, that was based upon United States patent application 11/295,635, filed on December 7, 2005. The entire disclosure of such published patent application and of patent application 11/295,635 is hereby incorporated by reference into this specification. Referring again to Figure 17, the device illustrated in such Figure differs from the device depicted in Figures 13-16 of published patent application 2006/0174790 in that the method of opening the scissors rollers to release the interleaf sheet differs. The scissors mechanism 200a is lowered in direction 234 by motor 2210b (not shown) until roller 204a contacts the scissor release roller 2007a. The scissor mechanism is then lowered further in direction 234. Since roller 204a is stopped by release roller 2007a, the scissor mechanism 200a pivots and then opens and the interleaf sheet 502 is released. Roller 204a has a clutch which rotates freely in direction 506 and the release roller 2007a is a free spinning roller so there is no resistance pulling the interleaf sheet 502 out of roller 204a and 2007a in direction 224. Another advantage of the free spinning release rollers is that there is very little wear of the urethane roller 204a. Scissor roller assembly 200b and release roller assembly 2007b operate in the same way as 200a and 2007a. Spring plungers 1208 and 2004 (not shown) push on the interleaf sheet 502 so that the interleaf sheet positively contacts the disposal rollers 302a and 302b. The disposal roller 302a rotates in direction 304a and disposal roller 302b rotates in direction 304b, thereby pulling the interleaf sheet.

The device depicted in Figures 12-17 provides many advantages. Separating the functions onto two arm assemblies allows the machine to load plates much faster into the imager than prior art devices because the arm does not have to let one operation finish before it starts the next. The arms work simultaneously to limit the waiting period between operations. This greatly increases throughput of the machine. In one embodiment, the Computer to Plate machine with the new dual pick up arm system can output 120 or more plates per hour compared to prior art machines, which typically output 60 plates per hour.

Figures 12-17 also illustrate a new method for releasing the interleaf sheets from the scissor mechanism. The interleaf removal arm moves the interleaf sheet over the disposal rollers. The scissor mechanism is lowered until the front roller of the scissor mechanism contacts a release roller. Then the scissor mechanism is lowered further forcing the scissors to open and release the interleaf sheet.

As will be apparent from such Figures 12-17, the device illustrated therein operates as follows: The plate pick up arm picks up a plate in the cassette using the vacuum cups and then brings the plate to the input shelf to be registered on the pins. As soon as the plate is out of the cassette, the interleaf sheet removal arm moves to pick up the interleaf sheet in the cassette. While the pick up arm is registering the plate against the pins, the interleaf sheet arm is picking up the interleaf sheet and the moving it to the disposal rollers and the rollers dispose the sheet in a holding bin below. The pick up arm finishes registering the plate and then only has to pause momentarily to allow the interleaf arm to finish disposing the interleaf sheet. Then the pick up arm can pick up the next plate.

Claims

We claim:

1. A system for removing an interleaf sheet contacting a plate sheet used in an imaging system, comprising:

(a) a substantially horizontal member;

(b) an assembly comprising at least two elements configured to directly contact and pick up the interleaf sheet, a portion of said assembly connected to said member;

(c) a motor configured to move said member in a direction substantially perpendicular to a surface of the interleaf sheet as positioned prior to contact; and

(d) a first sensor system that generates a signal indicating when said member is a first predetermined distance from the interleaf sheet;

(e) a second sensor system comprised of a second sensor that generates a signal indicating that the sheet beneath the second sensor is an interleaf sheet; said motor utilizing the first predetermined distance to move said member a second predetermined distance from the interleaf sheet, the at least two elements not contacting each other at the second predetermined distance, said motor moving said member in a direction toward the first predetermined distance to a position where at least a portion of the interleaf sheet is interposed between the at least two elements.

2. The system as recited in claim 1, wherein said system further comprises a third sensor that generates a signal when said interleaf sheet is disposed between said at least two elements.

3. The system as recited in claim 2, wherein said system is comprised of a first spring plunger.

4. The system as recited in claim 2, wherein said system is comprised of a second spring plunger.

5. The system as recited in claim 4, further comprising a disposal roller assembly that that receives said interleaf sheet from said at least two elements.

6. The system according to claim 5, further comprising a rail assembly configured to move said at least two elements to a position where said disposal roller assembly receives said interleaf sheet.

7. The system according to claim 6, further comprising a member that is aligned beneath the each of said at least two elements

8. The system according to claim 7, wherein the each of said at least two members comprises a roller.

9. The system according to claim 7 wherein said horizontal member is lowered in a direction toward the disposal roller assembly.

10. A system according to claim 9, wherein as said horizontal member is lowered in the direction toward said disposal roller assembly, each of said at least two elements engages one of said at least two members.

11. The system according to claim 10, wherein as said horizontal member continues to move in the direction of said disposal roller assembly, said at least one spring plunger directs said interleaf sheet to said disposal roller assembly.

12. The system according to claim 11, wherein as said horizontal member continues to move in the direction of said disposal roller assembly, each of said at least two elements engaging said at least two members cause said at least two elements to release said interleaf sheet to said disposal roller assembly.

13. A method for removing an interleaf sheet contacting a plate sheet used in an imaging system, comprising:

(a) providing a substantially horizontal member;

(b) providing an assembly comprising at least two elements configured to directly contact and pick up the interleaf sheet, a portion of the assembly connected to the member;

(c) moving the member in a direction substantially perpendicular to a surface of the interleaf sheet as positioned prior to the at least two elements contacting the interleaf sheet;

(d) generating a first signal indicating the member is above an interleaf sheet

(e) generating a second signal indicating when the member is a predetermined distance from the interleaf sheet;

(f) using the first predetermined distance to move the member to a second predetermined distance from the interleaf sheet, the at least two elements not contacting each other at the second predetermined distance;

(g) moving the member in a direction toward the first predetermined distance to a position where at least a portion of the interleaf sheet is held between the at least two elements; and

(h) generating a third signal indicating that the interleaf sheet is in place between the at least two elements.