US3645617A - Multiple image transfer device - Google Patents

Multiple image transfer device Download PDF

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Publication number
US3645617A
US3645617A US882644A US3645617DA US3645617A US 3645617 A US3645617 A US 3645617A US 882644 A US882644 A US 882644A US 3645617D A US3645617D A US 3645617DA US 3645617 A US3645617 A US 3645617A
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US
United States
Prior art keywords
image transfer
path
carriage
receiver
toner images
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US882644A
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English (en)
Inventor
John S Pollock
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Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Application granted granted Critical
Publication of US3645617A publication Critical patent/US3645617A/en
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0105—Details of unit
    • G03G15/0131—Details of unit for transferring a pattern to a second base

Definitions

  • the roiier segment is mounted in a carriage for movement along a path past a plu- 84 on 55 51 3g 3 mm 5" 3" rality of image transfer stations
  • a cycloidal cam surface controls rotational movement of the roller segment so that the toner images are transferred to the receiver substantially Field of without smearing.
  • the relatively large diameter of the roller segment assures a longer contact time at each station to assure [56] References Cited UNITED STATESPATENTS 2,986,466 5/1961 Kaprelian... 3,357,830 12/1967 more complete transfer than would result with a smaller radius transfer roller or roller segment.
  • This invention relates to transfer of an electrostatic toner image and more particularly to the transfer of a plurality of toner images in registry without smearing.
  • a plurality of photoconductive members may be charged and imagewise exposed to color separation negatives to form electrostatic images thereon. These images may then be developed by different colored developers to form color toner images. Finally, the toner images may be transferred in registry to a receiver to form a color print.
  • a receiver is wrapped around a roller which is moved along a linear path past a plurality of receiving stations wherein photoconductive members bearing toned electrostatic images are positioned for transfer by rolling contact of the receiver sequentially across each of the photoconductive members. In each instance, the.
  • an image transfer device which reduces the possibility of smearing and increases the contact time between a photoconductive member bearing a toner image and a receiver to which the image is to be'transferred over the contact time provided by prior art devices.
  • This is accomplished by utilizing a rotatable image transfer means having an arcuate surface in the form of at least a segment of a cylinder, the cylinder having a circumference which is greater than the pitch distance between two adjacent toner images at their respective transfer stations.
  • Pitch distance as used throughout the specification and claims means the distance between corresponding points on adjacent photoconductive members when the photoconductive members are at their respective transfer positions.
  • Means is provided for moving the image transfer means along a path past the transfer stations and cam means provides rotational movement of the arcuate surface across each of the toner images to effect transfer.
  • the rotational movement of the arcuate surface is controlled by the cam means as the image transfer means is moved along the path.
  • the transfer stations lie in a common plane.
  • the receiver is attached to an arcuate surface of a roller segment having a large diameter.
  • a rack and pinion arrangement imparts rotary motion to the roller segment upon translation of the roller along a path parallel to the common plane.
  • this rotary motion during transfer is retarded by a cycloidal cam adjacent each transfer station. This is possible through a slip clutch arrangement between the gears which interconnect the roller segment and the rack and pinion.
  • roller segment then rotates at a higher speed due to gear ratio of the gears which drive it through the rack and pinion so that it completes its circular motion in the time that the carriage is moved from the end of one transfer station to the beginning of the next transfer station so that the receiver will be in position to receive the next image.
  • the movement of the roller segment is controlled by the cycloidal cam at that station as previously described.
  • FIG. 1 is a fragmentary perspective view of a multiple image transfer device constructed in accordance with this invention
  • FIG. 2 is a diagrammatical section showing sequential positions of the image transfer means during movement from one transfer station to the next.
  • FIG. 3 is an offset vertical section, taken along line 3--3 of FIG. 2, showing a drive mechanism for the transfer device
  • FIG. 4 is a fragmentary section through a transfer station showing details of the transfer means and photoconductive member.
  • an image transfer device for sequentially transferring toner images to a receiver in registry from separate photoconductive members positioned in a common plane at equal pitch distances.
  • a plurality of photoconductive members such as photoconductive members P, P and P" are positioned in separate transfer stations.
  • Each photoconductive member includes a photoconductive surface or layer 2 on a conductive backing 4, as best seen in FIG: 4.
  • Each photoconductive member is moved into its respective transfer station from a development station, such as a liquid development station (not shown) by a transport 6 to which it is held, as by electromagnetic attraction.
  • Each transport is driven, as by a timing belt 7 connected to a suitable power source, not shown.
  • Each transfer station has registration pins 8, l0 and 12 respectively to space the photoconductive members at equal pitch distances D.
  • Carriage C includes a generally rectangular frame 14 mounted on spaced rails 16 and 18 by means of rollers 20 for movement along a path parallel to the common plane containing photoconductive members when they are in the transfer station.
  • the carriage may be driven as by motor, not shown, connected thereto, as by timing belt 22.
  • Image transfer device T is generally U-shaped, having an arcuate transfer element surface 24 supported between spaced legs 26 and 28.
  • Surface 24 may be coated with an elastomeric layer 30, such as conducting rubber, as best seen in FIGS. 1 and 4.
  • a suitable receiver, such as paper 32, which may have a conductive backing, now shown, is attached to conductive layer 30 as by clamps, such as clamps 34 shown in FIG. 3. These clamps have been shown by way of illustration only. It will be understood that other attaching devices such as spring clamps or vacuum means can be provided.
  • arcuate surface 24 takes the'form of a segment of the surface of a right circular cylinder having a circumference substantially greater than pitch distance D.
  • the arcuate surface 24 is mounted by means of legs 26 and 28 for rotation about a shaft 36, the shaft being joumaled in the walls of carriage frame 14 as shown.
  • Shaft 36 is rotatably driven by a pinion 38 which in turn is driven by a rack 40 extending parallel to the path of carriage C upon movementof the carriage along the path.
  • pinion 38 is mounted for rotation about shaft 36 on a sleeve 42 so that it does not directly drive shaft 36.
  • a small gear 44 is mounted for rotation about a stub shaft 46 extending from the side wall of frame 14 and forms part of a friction clutch.
  • gear 44 is provided with a disc 48 made of high-friction material and is urged into contact with the face of a large gear 50 by means of coil spring 52, as seen in FIG. 3.
  • large gear 50 is driven by small gear 44 through friction disc 48.
  • Gear 50 in turn drives a small gear 54 which is fixedly mounted on shaft 36 so that the shaft is turned thereby to rotate image transfer device T.
  • the gear train thus described results in image transfer device T being driven at a higher rotational velocity than pinion 38 when the friction clutch is not slipping.
  • a cam member 56 is provided adjacent each transfer station and has a cycloidal cam surface 58 engageable by a cam follower, such as roller 60 attached to an arm 62 extending from leg 28, as shown.
  • image transfer device T is in the position shown in solid lines at the left of FIG. 2 wherein the cam follower 60 is in engagement with the upper portion of cam surface 58 but arcuate surface 24 has not yet been brought into a position wherein a receiver attached thereto is in contact with photoconductive surface 2.
  • transfer device T will tend to be rotated in a counterclockwise direction by pinion 38 through the gear and clutch arrangement described above. However, the rotational movement of the image transfer device will be retarded by cam 56 so that a pure rotary motion of receiver 32 across photoconductive surface 2 is obtained so that any tendency to smear the transferred image is reduced.
  • a stop pin 64 which extends laterally from gear 54 is in engagement with a stop pin 66 extending from the hub of pinion 38, as best seen in FIGS. 2 and 3.
  • the gear ratios are such that pinion 38 tends to rotate faster than image transfer device T is permitted to rotate due to the cam 56. Slippage of pinion 38 with respect to image transfer device T is permitted through the friction clutch.
  • cam follower 60- will move downwardly along cycloidal cam surface 58 so that the image transfer device reaches position T as shown in FIG. 2, wherein the leading edge of receiver 32 comes in contact with photoconductive surface 2.
  • photoconductive member P and transport means 6 are held against the upward force exerted by the image transfer device, as by spaced stops 68. Stops 68 may be solid or resilient.
  • elastomeric layer 30 is flattened across a larger area by a large diameter surface than it would be if surface 24 had a smaller radius.
  • a potential may be applied to image transfer device T having a polarity opposite the charge on the toner particles.
  • This potential may be applied, as by a potential source 70 connected to cam 56.
  • a potential source 70 connected to cam 56.
  • it is desirable to increase this potential with each successive transfer whereupon a higher potential 72 can be applied through cam 56 at the next transfer station.
  • a still higher potential-74 can be applied at the next station, as seen in FIG. I.
  • a device for transferring a plurality of toner images in registry comprising:
  • image transfer means rotatable about a longitudinal axis and movable along a path past said transfer stations, said image transfer means having an arcuate surface in the form of at least a segment of a cylinder having a circumference which is greater than said pitch distance; means for moving said image transfer means along said path past said transfer stations and for rotating said image transfer means about said longitudinal axis during movement of said image transfer means along said path; and
  • cam means associated with each of said transfer stations engageable by said image transfer means for controlling rotational movement of said arcuate surface across each of said toner images to effect transfer thereof to said surface as said image transfer means is moved along said path.
  • cam means includes:
  • a cam follower on said image transfer means engageable with said camto restrict rotational velocity of said arcuate surface about said axis when said arcuate surface is in rolling engagement with said toner images.
  • a device as claimed in claim I, wherein said moving and rotating means includes:
  • a friction clutch interconnecting said pinion and said image transfer means for rotating said image transfer means as said carriage is moved along said path.
  • stop means for limiting relative rotation between said pinion and said image transfer means when said cam means is not controlling rotational movement.
  • said means further includes:
  • a device for transferring a plurality of toner images in registry onto a receiver at separate transfer stations comprising:
  • image transfer means rotatably mounted on said carriage about an axis extending transversely of said path and having an arcuate surface for holding the receiver, said surface being a segment of a cylinder about said axis having a circumference which is greater than said pitch distance;
  • a cam follower on said image transfer means engageable with each said cam as said receiver engages each respective photoconductive member to restrict said rotational velocity of said image transfer means as said receiver rolls across each photoconductive member when said carriage is moved along said path.
  • said rotating means includes:
  • friction clutch means in said gear train to permit relative movement between said image transfer means and at least part of said gear train when said cam follower is in engagement with one of said cams.
  • said rotating means includes:
  • a rack extending parallel to said path and positioned to be engageable by a gear in said gear train.
  • said gear train includes:
  • a pinion coaxially mounted with respect to said image transfer means and engageable with said rack for rotation upon movement of said carriage along said path;
  • a third gear mounted for rotation by said second gear for rotating said image transfer means, said third gear being smaller than said second gear.
  • said gear train includes:
  • stop means to limit relative movement between said gears when said cam follower is not in engagement with one of said earns.
  • a device for transferring a plurality of toner images in registry onto a receiver comprising:
  • image transfer means mounted on said shaft for rotation about said axis, said image transfer means having an arcuate surface spaced from said shaft for supporting a receiver for contact with toner images on said photoconductive members;
  • cam means located at each transfer station for engagement by said cam follower, for controlling the rotational velocity of said image transfer member during image transfer
  • clutch means for providing relative movement between said rotating means and said image transfer means during image transfer.
  • a device for transferring a plurality of toner images in registry onto a receiver comprising:
  • image transfer means mounted on said carriage for rotation about an axis parallel to and extending transversely of said path and having an arcuate surface for supporting a receiver, said surface being a segment of a cylinder having a circumference which is substantially greater than said pitch distance;
  • first means operative in response to movement of said carriage along said path, for rotating a receiver on said surface about said axis in a predetermined direction and successively into transfer contact with said photoconductive members, said first rotating means providing a predetermined rotational velocity in said predetermined direction for said arcuate surface during image transfer at said stations, said predetermined rotational velocity being coordinated with movement of said carriage by said moving means so that no slippage occurs between a receiver supported on said surface and said photoconductive members;

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Color Electrophotography (AREA)
US882644A 1969-12-05 1969-12-05 Multiple image transfer device Expired - Lifetime US3645617A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US88264469A 1969-12-05 1969-12-05

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US3645617A true US3645617A (en) 1972-02-29

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US882644A Expired - Lifetime US3645617A (en) 1969-12-05 1969-12-05 Multiple image transfer device

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US (1) US3645617A (fr)
BE (1) BE759767A (fr)
DE (1) DE2060163A1 (fr)
FR (1) FR2072759A5 (fr)
GB (1) GB1337126A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992011584A1 (fr) * 1990-12-24 1992-07-09 Eastman Kodak Company Appareil de developpement comprenant un systeme de translation des unites de developpement, utilise pour produire des images polychromes
US5243395A (en) * 1989-02-03 1993-09-07 Canon Kabushiki Kaisha Color image forming apparatus with developing unit moving means

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986466A (en) * 1955-12-06 1961-05-30 Edward K Kaprelian Color electrophotography
US3357830A (en) * 1961-08-03 1967-12-12 Xerox Corp Dyed image xerography
US3519343A (en) * 1968-07-01 1970-07-07 Eastman Kodak Co Image transfer mechanism
US3520603A (en) * 1968-07-01 1970-07-14 Eastman Kodak Co Image transfer mechanism

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986466A (en) * 1955-12-06 1961-05-30 Edward K Kaprelian Color electrophotography
US3357830A (en) * 1961-08-03 1967-12-12 Xerox Corp Dyed image xerography
US3519343A (en) * 1968-07-01 1970-07-07 Eastman Kodak Co Image transfer mechanism
US3520603A (en) * 1968-07-01 1970-07-14 Eastman Kodak Co Image transfer mechanism

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5243395A (en) * 1989-02-03 1993-09-07 Canon Kabushiki Kaisha Color image forming apparatus with developing unit moving means
WO1992011584A1 (fr) * 1990-12-24 1992-07-09 Eastman Kodak Company Appareil de developpement comprenant un systeme de translation des unites de developpement, utilise pour produire des images polychromes

Also Published As

Publication number Publication date
BE759767A (fr) 1971-05-17
DE2060163A1 (de) 1971-07-08
GB1337126A (en) 1973-11-14
FR2072759A5 (fr) 1971-09-24

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