US3839961A - Clamp device for clamping the trailing end portion of a sheet to the cylinder - Google Patents

Clamp device for clamping the trailing end portion of a sheet to the cylinder Download PDF

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Publication number
US3839961A
US3839961A US00352680A US35268073A US3839961A US 3839961 A US3839961 A US 3839961A US 00352680 A US00352680 A US 00352680A US 35268073 A US35268073 A US 35268073A US 3839961 A US3839961 A US 3839961A
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United States
Prior art keywords
sheet
cylinder
roller
end portion
trailing end
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Expired - Lifetime
Application number
US00352680A
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English (en)
Inventor
K Murata
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Ricoh Co Ltd
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Ricoh Co Ltd
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Publication date
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Publication of US3839961A publication Critical patent/US3839961A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41L—APPARATUS OR DEVICES FOR MANIFOLDING, DUPLICATING OR PRINTING FOR OFFICE OR OTHER COMMERCIAL PURPOSES; ADDRESSING MACHINES OR LIKE SERIES-PRINTING MACHINES
    • B41L29/00—Devices for attaching printing elements or formes to supports
    • B41L29/12—Devices for attaching printing elements or formes to supports for attaching flexible printing formes
    • B41L29/14—Clamping devices
    • B41L29/16—Clamping devices operating automatically during operation of rotary machines to attach the printing formes to the forme cylinders

Definitions

  • ABSTRACT A device comprising clamp means for clamping the trailing end portion of a sheet to one wall surface of a cutout formed in the cylinder after the leading end portion of the sheet is gripped by a portion of the peripheral surface of the cylinder whereby the trailing end portion of the sheet can be clamped to the cylinder 8 Claims, 10 Drawing Figures PATENTED BET 1974 SE51 1 0f 2 FIG.
  • This invention relates to clamp devices, and more particularly it is concerned with a device for clamping the trailing end portion of a sheet, such as a master sheet or photosensitive sheet used for offset printing apparatus or electrophotographic copying apparatus,
  • a plurality of openings are formed in the leading and trailing end portions of the master plate to receive therein locking claws provided in a cutout formed in thema'ster cylinder so as to clamp both the leading and trailing end portions of the master plate to the master cylinder.
  • This device is inconvenient, however, because the master plate must be mounted cylinder after stopping the ro-' tation thereof. 7
  • An object of this invention is to provide a device for automatically. clamping the trailing end portion of a sheet to a cylinder or drum while the latter is rotating.
  • Another object of the invention is to provide a device for automatically clamping the trailing end portion of a sheet to a cylinder or drum while the latter is rotating, comprising flexing means for moving the trailing end portion of a sheet away from a cutout formed in the cylinder in preparation for clamping the trailing end portion of the sheet to the cylinder.
  • the invention permits a sheet to be mounted automatically on the cylinder and uniformly brought into intimate contact with the periphery of the cylinder without requiring manual attention.
  • the duplicating apparatus of the type described of the'prior art have the disadvantage of exposure of the photosensitive sheet to an optical image of an original not being carried out satisfactorily and portions of the image in the trailing end portion of the sheet becoming unclear, because the trailing end portion of the sheet is free to move.
  • FIG. 4 is a side viewof the cam for driving the displacing roller and the and roller cooperating with the cam;
  • FIG.- 5 is a side view of the arm placing roller.
  • FIG. -1 a master cylinder 1 is rotatably supported .by a
  • the grip claws 5 are urged to pivot clockwise in FIG. 1 by the biasing force of a spring (not shown) and normally maintained in pressing engagement with a planar portion of the cutout 4.
  • a plate supply command is given to the master cylinder 1
  • the plate grip claws 5 are moved to a phantom line position so as to grip a master plate 8 when the latter is supplied.
  • the plate grip device constructed as aforementioned is known,
  • the device provided by the invention comprises a hold-down roller 11 and a flexing roller '12 disposed near the periphery of the master cylinderl and norspring 18 connected at one end to an immovable memsupporting the disber 16 and at the other end to a pin 17 planted on one of the arms 14.
  • the flexing roller 12 is rotatably supported by a shaft 21 supported at opposite ends by a pair of arms 22 shown in phantom line positions.
  • the arms 22 are pivotally supported by a shaft 23 supported by the opposite side walls.
  • the flexing roller 12 is made of a material which has a higher coefficient of friction than the material for the master cylinder 1 relative to the master plate 8.
  • a sector gear 28 which is supported at its base by a shaft 29 connected to one of the opposite side plates.
  • the sector gear 28 supports through a shaft a follower roller 31 which is juxtaposed to a cam 50 (See FIG. 4) secured, for example, to the shaft 2 supporting the master cylinder 1 and capable of sliding axially of the shaft 2.
  • the sector gear 28 is adapted to make one pivotal movement in suitable timing when the cam 50 makes one complete revolution together with the master cylinder 1.
  • the device according to the invention further comprises clamp means comprising a plurality of clamp members 34 each including a claw 34a at a free end thereof and disposed in the relatively large cutout 4 formed in the master cylinder, with the claws 34a being normally maintained in pressing engagement with a wall surface 33 of the cutout 4 opposite to the wall surface with which the grip claws 5 are maintained in engagement. More specifically, each claw 34a has secured to its underside a friction member 35 which is maintained in pressing engagement with the wall surface 33.
  • Each clamp member 34 is connected at its base by a screw 37 to a bent portion 36a of a slider 36 which is formed therein with slots 38 and 39 loosely receiving therein pins 41 and 42 respectively which are planted on one side of the master cylinder 1.
  • Planted on the slider 36 is a pin 43 which is loosely received in a fork 44a formed at one end portion of a follower lever 44 which supports a roller 45 at the other end portion through a shaft.
  • the follower lever 44 which is pivotally supported by a shaft 46 connected to one side of the master cylinder 1 is urged to pivot counter clockwise about the shaft 46 in FIG. 1 by the biasing force of a compression spring 48 connected at one end to a pin 47 planted on the master cylinder 1 and at the other end to the lever 44.
  • the roller 45 is juxtaposed to a cam (not shown) mounted, for example, on the shaft 2.
  • a cam (not shown) mounted, for example, on the shaft 2.
  • the follower lever 44 pivots clockwise about the shaft 46 in FIG. 1.
  • the cam is moved to a position in which it is disposed in the path of movement of the roller 45 only when it is desired to cause the follower lever 44 to pivot or when the master plate is to be mounted on the master cylinder 1.
  • the cam is spaced apart from the roller 45 or disposed in a position which is vertically spaced apart from the plane of FIG. 1.
  • the hold-down roller 1 l and flexing roller 12 are disposed in the respective phantom line positions 11A and 12A when no master plate is mounted on the master cylinder 1.
  • the roller 11 is brought into pressing engagement with the periphery of the master cylinder 1 by the action of the cam so as to bring the master plate 8 into intimate contact with the periphery of the master cylinder 1.
  • the flexing roller 12 rotates clockwise while the master cylinder l rotates counter clockwise as indicated by the arrow 3, so that portions of the peripheries of roller 12 and master cylinder 1 in contact with each other momentarily move in the same direction.
  • the peripheral velocity of the roller 12 is about twice that of the master cylinder 1.
  • FIG. 2a shows the flexing roller 12 beginning to be brought into pressing engagement with the periphery of the master cylinder 1 as the trailing end portion 8a of the master plate 8 draws near the flexing roller 12. Since the flexing roller 12 rotates in a direction opposite to the direction of rotation of the master cylinder 1 and at a speed higher than that of the master cylinder, a portion of the master plate 8 is turned up in the direction of rotation of the cylinder 1 by the roller 12 on the periphery of the master cylinder 1 to form a flexed portion 51 as shown in FIG. 2b. By this action of the flexing roller 12, the trailing end portion 8a is moved upwardly from the cutout 4 to the periphery of the master cylinder 1. While the flexing roller 12 rotates, the master cylinder 1 rotates through about 40 in the direction of the arrow 3.
  • the flexing roller 12 stops rotating.
  • the master cylinder 1 continues to rotate in the direction of the arrow 3, so that the trailing end portion 8a is brought almost to a standstill by the frictional dragging of theflexing roller 12 on the master plate 8 and the flexed portion 51 is reduced in size, till the flexed portion 51 disappears and the master plate 8 is brought into intimate engagement with the master cylinder throughout its length as shown in FIG. 20.
  • the trailing end portion 8a extends above the cutout 4.
  • the claws 34a reach the end of their radial movement and move into a position in which they are disposed above the trailing end portion 8a of the master plate 8 and disposed nearest the flexing roller 12. Then the claws 34a move downwardly into pressing engagement with the trailing end portion 8a so as to force the latter tightly over the wall surface 33, thereby clamping the trailing end portion 8a to the master cylinder 1. As soon as the claws 34a move downwardly to force the trailing end portion 8a against the wall surface 33, the hold-down roller 11 and flexing roller 12 are restored to the respective phantom line positions 11A and 12A.
  • FIG. 3a Clamping the trailing end portion of the master plate to the master cylinder will be described with reference to FIG. 3.
  • the trailing end portion 8a of the master plate 8 extends above the clamp members 34 and prevents the upward movement of the claws 34a.
  • the trailing end portion 8a is displaced in the direction of movement of the master cylinder by the flexing roller 12 to 'form the flexed portion 51 as shown in FIG. 3b.
  • the trailing end portion 8a extends above the cutout 4 and beneath the claws 34a.
  • clamp members 34 are returned to their original position and the flexing roller 12 is moved to its phantom line position, whereby the trailing end portion 8a of the master plate 8 can be forced tightly over the wall surface as shown in FIG. 3d and clamped to the master cylinder 1.
  • a clamp device for clamping the trailing end portion of a sheet to the periphery of a cylinder provided with means for gripping the leading end portion of the sheet comprising a sheet hold-down roller adapted to bring the sheet into pressing engagement with the periphery of the cylinder when the sheet is gripped at its leading end portion by the grip means and the sheet has moved beneath the hold-down roller, sheet flexing means disposed in the vicinity of said sheet hold-down roller and posterior thereto with respect to the direction of rotation of the cylinder and adapted to be brought into pressing engagement with the sheet as the trailing end portion of the sheet draws near the sheet flexing means so as to turn up a portion of the sheet in the direction of rotation of the cylinder and form a flexed portion in the sheet, clamp means provided in the cylinder and each including a free end portion adapted to move into and out of engagement with one wall surface of a cutout formed in the periphery of the cylinder, and means causing said clamp means to move outwardly away from the periphery of
  • said clamp means comprises a plurality of clamp elements each having a free end positionable to press the trailing end portion of a sheet against said one wall surface of said cutout, and wherein said means causing said clamp means to move includes a member mounted on said cylinder for reciprocating motion in a direction generally radial of said cylinder and secured to said clamp elements, and means for reciprocating said lastmentioned member to cause successive outward and inward movement of said clamp elements.
  • said sheet flexing means comprises a roller adapted to rotate in a direction opposite to the direction of rotation of the cylinder when the trailing end portion of the sheet draws near the flexing means, so that portions of the peripheries of the roller and the cylinder in contact with each other momentarily move in the same direction, said roller having a peripheral velocity higher than the peripheral velocity of the cylinder.
  • said sheet flexing means further includes means for moving said last-mentioned roller into and out of a position for pressing a sheet against the periphery of said cylinder, and means for rotating said last-mentioned roller in a direction opposite to the direction of rotation of said cylinder in synchronism with movement of said roller into sheet-pressing position by said moving means, such that rotation of said last-mentioned roller in said opposite direction begins upon movement of said lastmentioned roller into sheet-pressing position and terminates prior to movement of said last-mentioned roller out of sheet-pressing position.
  • said means for rotating said last-mentioned roller includes a cam rotated with said cylinder and cam follower means for imparting to said last-mentioned roller a predetermined extent of angular displacement in correspondence with rotation of said cam.
  • said means for moving said last-mentioned roller includes a pair of arms rotatably supporting said last-mentioned roller and pivotable about an axis fixed in relation to the axis of rotation of said cylinder.
  • a device further including means for moving said sheet hold-down roller into and out of a position for pressing a sheet against the periphery of said cylinder.
  • said means for moving said sheet hold-down roller includes a pair of arms rotatably supporting said sheet hold-down roller and pivotable about an axis fixed in relation to the axis of rotation of said cylinder.

Landscapes

  • Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
  • Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
US00352680A 1972-04-28 1973-04-19 Clamp device for clamping the trailing end portion of a sheet to the cylinder Expired - Lifetime US3839961A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4273472A JPS5513910B2 (de) 1972-04-28 1972-04-28

Publications (1)

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US3839961A true US3839961A (en) 1974-10-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00352680A Expired - Lifetime US3839961A (en) 1972-04-28 1973-04-19 Clamp device for clamping the trailing end portion of a sheet to the cylinder

Country Status (4)

Country Link
US (1) US3839961A (de)
JP (1) JPS5513910B2 (de)
DE (1) DE2321427C3 (de)
GB (1) GB1392276A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4161358A (en) * 1977-02-01 1979-07-17 Grafosol, S.p.A. Sheet supporting drum during development in machines for electrostatically preparing printing matrices
US4183652A (en) * 1977-04-30 1980-01-15 Ricoh Company, Ltd. Photoconductor sheet clamp apparatus
US4219272A (en) * 1978-04-20 1980-08-26 Olympia Werke Ag Electrophotographic copier with replaceable photoconductive sheet
US4268158A (en) * 1976-12-23 1981-05-19 Toppan Printing Co., Ltd. Dry planographic printing apparatus
US4277164A (en) * 1978-07-14 1981-07-07 Olympia Werke Ag Photocopier photoconductive sheet holding device
US5052299A (en) * 1989-03-30 1991-10-01 Akiyama Printing Machine Manufacturing Company Ltd. Plate clamping apparatus for a leaf-type printing machine
US5410391A (en) * 1993-04-22 1995-04-25 Toyo Ink Manufacturing Co., Ltd. Image-transfer apparatus with movable smoothing roller and image-transfer method
US5931589A (en) * 1997-05-23 1999-08-03 Toshiba Tec Kabushiki Kaisha Ink-jet printer having a printing medium wrapping apparatus

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2760142C2 (de) * 1976-06-02 1985-11-21 Mita Industrial Co., Ltd., Osaka Elektrophotographisches Kopiergerät
JPS55124659A (en) * 1979-03-19 1980-09-25 Ricoh Co Ltd Master clamp device in printing press
DE4004352C1 (de) * 1990-02-13 1991-06-06 Heidelberger Druckmaschinen Ag, 6900 Heidelberg, De

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203074A (en) * 1962-06-04 1965-08-31 Litton Systems Inc Sheet clamping arrangements
US3375781A (en) * 1965-09-30 1968-04-02 Xerox Corp Registration mechanism for a reproduction machine
US3427965A (en) * 1965-09-30 1969-02-18 Xerox Corp Sheet gripper means for reproduction machine of the pressure-transfer type
US3664260A (en) * 1970-06-15 1972-05-23 Addressograph Multigraph Master sheet retainer for printing machines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203074A (en) * 1962-06-04 1965-08-31 Litton Systems Inc Sheet clamping arrangements
US3375781A (en) * 1965-09-30 1968-04-02 Xerox Corp Registration mechanism for a reproduction machine
US3427965A (en) * 1965-09-30 1969-02-18 Xerox Corp Sheet gripper means for reproduction machine of the pressure-transfer type
US3664260A (en) * 1970-06-15 1972-05-23 Addressograph Multigraph Master sheet retainer for printing machines

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4268158A (en) * 1976-12-23 1981-05-19 Toppan Printing Co., Ltd. Dry planographic printing apparatus
US4161358A (en) * 1977-02-01 1979-07-17 Grafosol, S.p.A. Sheet supporting drum during development in machines for electrostatically preparing printing matrices
US4183652A (en) * 1977-04-30 1980-01-15 Ricoh Company, Ltd. Photoconductor sheet clamp apparatus
US4219272A (en) * 1978-04-20 1980-08-26 Olympia Werke Ag Electrophotographic copier with replaceable photoconductive sheet
US4277164A (en) * 1978-07-14 1981-07-07 Olympia Werke Ag Photocopier photoconductive sheet holding device
US5052299A (en) * 1989-03-30 1991-10-01 Akiyama Printing Machine Manufacturing Company Ltd. Plate clamping apparatus for a leaf-type printing machine
US5410391A (en) * 1993-04-22 1995-04-25 Toyo Ink Manufacturing Co., Ltd. Image-transfer apparatus with movable smoothing roller and image-transfer method
US5931589A (en) * 1997-05-23 1999-08-03 Toshiba Tec Kabushiki Kaisha Ink-jet printer having a printing medium wrapping apparatus

Also Published As

Publication number Publication date
GB1392276A (en) 1975-04-30
DE2321427B2 (de) 1975-02-20
JPS492607A (de) 1974-01-10
DE2321427A1 (de) 1973-11-29
DE2321427C3 (de) 1975-09-25
JPS5513910B2 (de) 1980-04-12

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